Fix ^, $, add case sensitivity override in search

[parkovski]

• Fixes Search for end of line ($) returns end of file #2086 and Can't search using caret ^ (Regex starts-with) #2101 by adding the 'm' flag to the search regex, which causes ^ and $ to match per-line instead of per-file.
• Implements Case sensitive search option - \c / \C #2100 by stripping all \c and \C from the search pattern and changing ignorecase for that search based on the first one found - this mimics vim's behavior.

Substitute is not affected by either of these issues - ^ and $ already work there, and /i to override case is already implemented - vim doesn't support \c there.

[jpoon]

LGTM. Fix the build error and then we can merge.

Compile with gulp first (to format things properly with prettier) before pushing!"; sleep 1; exit 1; }; else echo "Prettier passed."; fi

[parkovski]

When I run gulp locally nothing changes - it's giving the same error for all the recent PRs for changes none of them made.

[parkovski]

I see what's wrong, I had an older version of prettier than travis. Should I add the fixed files to this PR, and if so should I update package.json? Since the version of prettier listed may not work.