company--insert-candidate: Insert before overlays that begin at point

That fixes `company-with-candidate-inserted' to work with the way the
pseudo-tooltip overlay is now rendered (at the end of the current line).
company-pseudo-tooltip-show: Improve tooltip-guard results
company-pseudo-tooltip-guard: Handle wrapped lines
Release 0.8.5
Fix company-yasnippet compilation without yasnippet

Closes #187
Use read-kbd-macro instead of kbd as a function.

In Emacs 24.1 and 24.2, kbd was a macro and not a function,
so that a call like (kbd (format ...)) would fail. Use
read-kbd-macro instead, which works for all Emacsen in 24.x.
Merge pull request #191 from jorgenschaefer/master

Use read-kbd-macro instead of kbd as a function.
company-gtags: Don't try to complete in non-file buffers
company--insert-candidate: Don't use `insert-before-markers'

Fixes #189.

Apparently, it's enough to pass t REAR-ADVANCE agrument to `make-overlay' when
creating the pseudo-tooltip overlay.
company-search-printing-char: Don't update company-search-string when no match

Fixes #194
company-create-match-predicate: Just replace the predicate

Building on the previous one is ridiculous, because the main use case is
company-search-mode, and any previous search string is a prefix of the current
one.  With company-filter-candidates, it was especially wasteful.
company-post-command: Handle being called after quitting

Fixes #190
company-files.el: Change regexp prefix

* Fix Windows drive letters recognition.
* Complete relative paths, starting with ./ or ../.
Update docstring, change words, bump copyright year
company-files-complete: Include mtime in the cache key
Update NEWS; do the forgotten version bump
Update a comment
company-files.el: Use the "private function" naming convention
company-files: Fix cache behavior for when we're backspacing

As discussed
in https://github.com/Lompik/company-mode/commit/528cd1b4c94e1d6b0009068be618bde2b27ec583#commitcomment-7953472.
company-file--keys-match-p: Handle OLD being nil