cleanup contact form generator

+ adds generator tests
+ rename from contact_form to contact_page
+ extended USAGE and CHANGELOG
+ added command line options
+ bugfix: translations and translates controller message
+ makes it possible to set the redirect after submit page in the CMS
+ fixes MissingAttribute not returning the default value
updates README with testing section

+ bugfix: google analytics specs
+ adds google analytics and contact page component to the integration tests