Add ZSH completion

[VorpalBlade]

This is mostly a write of zsh completion from scratch, only partly based on the code in #39 (comment). I couldn't reuse most of it since it didn't follow zsh style guideline (use lower case in the help messages) and was also outdated and missing several options.

I believe these completions should be accurate as of 1.5.0 (latest version and latest commit as of writing this).

[VorpalBlade]

One thing I'm not completing (and nor is the bash completion, so I don't consider this a big issue) is config parameter override on the command line.

This could be done, though I prefer to have a hidden command to tlp that lists valid variable names rather than hard coding the list of these in both the zsh and bash completion (and possibly fish completion in the future if someone wants to write that). Completing arguments to those config flags would be more difficult though.

[linrunner]

Hi,

this is really great, 9 years after #39. Give me a little time to examine.

[linrunner]

Solves #39

[linrunner]

Well, this already looks very promising. Please iron out the small problems (see comments).

[linrunner]

ps. config parameter override is actually intended as a test tool and not for users. A completion would be great, of course, but I'm also very happy with your contribution without that.

[VorpalBlade]

I believe those issues should be fixed now.

[linrunner]

Right. Thank you very much for your contribution.

As I have no experience with the zsh, I would be grateful if you could stay tuned in case of issues.

[VorpalBlade]

Not a problem, I tag me in any relevant issues and I should be able to respond (though it may take a few days, or weeks later during the summer, when I will be on a completely offline vacation with a backpack and tent).