add google analytics generator
refactored sources of the google_analytics module
add rspec tests for google_analytics component
added documentation for google analytics component
Merge branch 'develop' into feature/google_analytics

* develop:
  load kickstarter only in test and development mode
  extended flash messages
  minor cleanup
refactoring

+ uses Cells instead of helper and partials
+ adds optional generator arguments for tracking id and anonymize ip setting
+ bugfix: naming of variables in model was not correct
+ updates README, USAGE and CHANGELOG
+ adds test if migration file is created and setup correctly
Merge pull request #1 from infopark/feature/google_analytics

Feature/google analytics