add google-auth and service-config packages to Meteor
+ Remove 'accounts-twitter' & 'accounts-facebook' packages
+ Remove share options in config and html template
+ Remove unnecessary user edit form fields
+ add 'appendto.com' email restriction for signup
+ update Router pre-action to redirect on not logged in, except on the signin and signup pages
+ update 'getUserName' to be nice with google service.
Merged in changes from a2-build
Merge pull request #5 from appendto/google-auth

Google auth