Adding action properties required for TwitterTheme:
Adding action properties required for TwitterTheme:

* icon (holds icon class name [reference](http://twitter.github.com/bootstrap/base-css.html#icons))
* class (holds button class name [reference](http://twitter.github.com/bootstrap/base-css.html#buttons))

Adding getters and setters for new properties.

Restless-ET/AdmingeneratorGeneratorBundle,Restless-ET/AdmingeneratorGeneratorBundle,symfony2admingenerator/AdmingeneratorGeneratorBundle,Restless-ET/AdmingeneratorGeneratorBundle,symfony2admingenerator/AdmingeneratorGeneratorBundle