Highlighting of matches should be done with the same case-folding that
filtering is done with! This is perhaps most noticeable with
orderless-smart-case on, but was previously incorrect with it off
since filtering used completion-ignore-case and highlighting used
case-fold-search!

Add note about custom styles for `company-capf'

Fix #119 using @minad's suggestion.

Improve orderless-try-completion (Fix #118)

I know, I know, but I'm used to a non-maximized Emacs frame.

Fix 121

orderless-try-completion abuses a "predicate" which throws as a fast loop over
the completion candidate.

- The predicate returns t such that all-completions returns a list (instead of
  nil as before). This fixes completion-table-with-predicate.

- If multiple candidates match, we check that the matches are actually
  different. This ensures that we don't get incorrect results if the predicate
  is called twice on the same candidate or if duplicates exists.