* Added support for configuring google analytics
* Adding a configuration parameter 'ga_key' under DXR section
  will publish google analytics snippet in all templates
  this will require rebuilding the templates
* Renamed google analytics configuration key as 'google_analytics_key'
  from existing 'ga_key'
* Documented google_analytics_key in configuration.rst
  Fixes some issues with the last commit
* Added test to verify non-existance of google analytics snippet
* Added tests to check google analytics snippet
* remove the import of 'run'
* Fix test names and doc strings
* Add a test file required to build
Merge Google Analytics support. Fix bug 1045204. Close #332.