GWT 2.6.1, Guava 18, RichFaces 4.5

TODO

 - [x] Update to RichFaces 4.5.0.GA (when available)

On hold until we can get the breaking functional tests to work (especially table update problems):

 - [x]  EditTranslationMemoryTest.mustClearBeforeDelete (`@Ignore`d: intermittent)
 - [x]  TranslationHistoryTest.compareTranslationHistory (`@Ignore`d: intermittent)
 - [x]  EditHomePageTest.editPageContent
 - [x]  VersionGroupTest.addANewProjectVersionToAnEmptyGroup