Replace github refference with link travis-ci/travis-ci#1266

Github issue refference is now replaced with github issue url.
This covers following refferences:
* #Num
* User#Num
* User/Project#Num
Simplified code in github refference linking
More github references replaced with links

Github links will be created for following references:
* @username
* gh-1 (for issue #1)
Delegate CurrentUserController#updateLocale to user instance