[WIP] Support multiple @find-by annotations

Still open tasks but basic support for multiple ```@find-by```. Still requiring some new unit tests and ```ElementCollection``` see #48 for more details.

Closes #13
It's not the feature added in latest PhpStorm: http://blog.jetbrains.com/webide/2013/03/change-signature-refactoring-in-phpstorm/ . Was there since PhpStorm 6.x it seems.

On Mac I place cursor on parameter and press Command+T (Refactor This) shortcut. Then menu opens and I select "Change Signature ...".