~30 golangci-lint warnings on codebase

[cameronelliott]

I currently use this as golangci-lint run my vs-code go linter.
I have used it for about a year on a WebRTC SFU: deadsfu
(see the image at the end for vscode setup)

I do not find it overly verbose, and I find it does a near perfect identification (separation) of issues I would want fix vs ignore.
(the main issue with many linters)

I noticed about 20-30 issues with gostatic, that seem like the project would benefit from if fixed.

@piranha Do you think these should be cleaned up? (ignoring who/when etc right now)

c@macmini ~/D/gostatic (master)> golangci-lint run

hotreload/core.go:109:5: `htmlRe` is unused (deadcode)
var htmlRe = regexp.MustCompile("\btext/html\b")
    ^
lib/utils.go:44:6: `drainchannel` is unused (deadcode)
func drainchannel(out chan string) {
     ^
gostatic.go:21:2: `ExitCodeOk` is unused (deadcode)
	ExitCodeOk = 0
	^
gostatic.go:25:2: `ExitCodeInvalidConfig` is unused (deadcode)
	ExitCodeInvalidConfig = 2
	^
utils.go:21:6: `errexit` is unused (deadcode)
func errexit(err error) {
     ^
utils.go:33:6: `debug` is unused (deadcode)
func debug(format string, args ...interface{}) {
     ^
hotreload/core.go:150:10: Error return value of `w.Write` is not checked (errcheck)
		w.Write(Morphdom)
		       ^
hotreload/core.go:151:10: Error return value of `w.Write` is not checked (errcheck)
		w.Write(Script)
		       ^
hotreload/watch.go:21:14: Error return value of `watcher.Add` is not checked (errcheck)
		watcher.Add(fn)
		           ^
hotreload/watch.go:43:17: Error return value of `watcher.Add` is not checked (errcheck)
					watcher.Add(ev.Name)
					           ^
hotreload/watch.go:45:20: Error return value of `watcher.Remove` is not checked (errcheck)
					watcher.Remove(ev.Name)
					              ^
hotreload/watch.go:56:16: Error return value of `filepath.Walk` is not checked (errcheck)
		filepath.Walk(path, watchAll(watcher))
		             ^
hotreload/watch.go:59:14: Error return value of `watcher.Add` is not checked (errcheck)
		watcher.Add(path)
		           ^
lib/example.go:172:11: Error return value is not checked (errcheck)
	WriteFile(dir, "config", ExampleConfig)
	         ^
lib/example.go:173:11: Error return value is not checked (errcheck)
	WriteFile(dir, "Makefile", ExampleMakefile)
	         ^
lib/example.go:174:11: Error return value is not checked (errcheck)
	WriteFile(dir, "site.tmpl", ExampleTemplate)
	         ^
lib/header.go:141:16: Error return value of `yaml.Unmarshal` is not checked (errcheck)
	yaml.Unmarshal([]byte(source), &m)
	              ^
lib/page.go:74:12: Error return value of `page.Peek` is not checked (errcheck)
		page.Peek()
		         ^
lib/page.go:256:15: Error return value of `page.Process` is not checked (errcheck)
		page.Process()
		            ^
lib/site.go:86:15: Error return value of `filepath.Walk` is not checked (errcheck)
	filepath.Walk(site.Source, site.collectFunc(errors))
	             ^
lib/template_funcs.go:55:16: Error return value of `io.WriteString` is not checked (errcheck)
	io.WriteString(h, value)
	              ^
lib/template_funcs.go:199:17: Error return value of `io.WriteString` is not checked (errcheck)
		io.WriteString(stdin, text)
		              ^
processors/pagination.go:143:15: Error return value of `listpage.Peek` is not checked (errcheck)
	listpage.Peek()
	             ^
processors/tags.go:68:16: Error return value of `tagpage.Peek` is not checked (errcheck)
			tagpage.Peek()
			            ^
gostatic.go:92:24: Error return value of `gostatic.WriteExample` is not checked (errcheck)
		gostatic.WriteExample(target)
		                     ^
hotreload/core.go:30:2: `dirs` is unused (structcheck)
	dirs     []string
	^
hotreload/core.go:31:2: `files` is unused (structcheck)
	files    []string
	^
lib/site.go:25:2: `mx` is unused (structcheck)
	mx sync.Mutex
	^
lib/config.go:160:5: S1011: should replace loop with `cfg.Templates = append(cfg.Templates, files...)` (gosimple)
				for _, fn := range files {
				^
lib/config.go:96:20: S1003: should use strings.Contains(line, "=") instead (gosimple)
		if level == 0 && strings.Index(line, "=") != -1 {
		                 ^
lib/header.go:145:10: S1034: assigning the result of this type assertion to a variable (switch value := value.(type)) could eliminate type assertions in switch cases (gosimple)
		switch value.(type) {
		       ^
lib/header.go:149:31: S1034(related information): could eliminate this type assertion (gosimple)
			temp := make([]string, len(value.([]interface{})))
			                           ^
lib/header.go:150:22: S1034(related information): could eliminate this type assertion (gosimple)
			for i, v := range value.([]interface{}) {
			                  ^
lib/header.go:155:41: S1034(related information): could eliminate this type assertion (gosimple)
			cfg.SetValue(key, strconv.FormatBool(value.(bool)), &s)
			                                     ^
processors/template.go:53:10: S1028: should use fmt.Errorf(...) instead of errors.New(fmt.Sprintf(...)) (gosimple)
		return errors.New(fmt.Sprintf("%s: %s", page.Source, err))
		       ^
lib/page.go:293:24: S1002: should omit comparison to bool constant, can be simplified to `page.Hide` (gosimple)
	case "Hide": return ((page.Hide == true && value == "true") ||
	                      ^
lib/page.go:294:4: S1002: should omit comparison to bool constant, can be simplified to `!page.Hide` (gosimple)
		(page.Hide == false && value == "false"))
		 ^
hotreload/core.go:78:2: unreachable: unreachable code (govet)
	s.Lock()
	^
hotreload/core.go:71:15: unusedresult: result of fmt.Errorf call not used (govet)
				fmt.Errorf("error: %s", err)
				          ^
hotreload/core.go:95:13: unusedresult: result of fmt.Errorf call not used (govet)
		fmt.Errorf("can't establish WebSocket connection: %s", err)
		          ^
processors/template.go:45:3: SA9003: empty branch (staticcheck)
		if err := recover(); err != nil {
		^
lib/page.go:126:30: SA5011: possible nil pointer dereference (staticcheck)
	url := strings.Replace(page.Path, string(filepath.Separator), "/", -1)
	                            ^
lib/page.go:123:5: SA5011(related information): this check suggests that the pointer can be nil (staticcheck)
	if page == nil {
	   ^

my vscode setup:

[piranha]

Yeah most of those is an old cruft or me being lazy, right? Fixing this is obviously a nice thing. :)