Merge branch 'release/2.1.1' into develop
Added backend for company-mode.

Closes #11.
Fix function argument annotations in company-mode
Rename `arguments' to `prototype'  in php-extras-company
Merge pull request #12 from joddie/company-mode-fix

Fix function argument annotations in company-mode
Fixed spelling error in documentation.
Documented support for company-mode.
Bumped version number.
Merge branch 'release/2.2.0'