Enhancement #43: Track events for key actions in Google Analytics

A GoogleAnalyticsEvent and a GAEventData were created to easily fire application
wide events. This event is handled in BoostrapperImpl and will track an event in
Google Analytics. Events in following Presenters are fired:

 - PhenotypeUploadPresenterWizard (upload + error)
 - GWASUploadPresenterWizard (upload + error)
 - IsaTabUploadPresenterWizard (upload + error)
 - BasicStudyWizardPresenter (study create + error)
 - StudyDetailPresenter (studyjob + error)
 - GWASPlotPresenterWidget (view + error)