create mobile push notifications branch

git-svn-id: http://plugins.svn.wordpress.org/jetpack/branches/mobile-push-notifications@594635 b8457f37-d9ea-0310-8a92-e5e31aec5664
- Expose the plugin version on the XML-RPC layer.
- Expose the .COM blog_id on the XML-RPC layer.
- Synchronize comments even if they are in 'pending'.

git-svn-id: http://plugins.svn.wordpress.org/jetpack/branches/mobile-push-notifications@594641 b8457f37-d9ea-0310-8a92-e5e31aec5664