Use some features only in certain modes

Use fontify meta, multiple function signatures and post completion
templatifying only in some modes.
Update and rename ycmd-autocomplete.el to auto-complete-ycmd.el

This needs to be done in order to use `(require 'auto-complete-ycmd)`
Merge pull request #124 from ptrv/extended-features

Use some features only in certain modes
Merge pull request #125 from milkypostman/patch-1

Update and rename ycmd-autocomplete.el to auto-complete-ycmd.el