fix XMLRPC error message cleaning to unescape HTML strings
fix #250: show a VideoPress alert for WP.com blogs
when the user wants to upload a video on a WP.com blog and VideoPress is
disabled.
New _Learn More_ button added to the error dialog saying _You should install VideoPress to upload video to your WP.com blog_ in PostsActivity
New _Learn More_ button added to the dialog saying _You should install VideoPress to upload video to your WP.com blog_ in MediaBrowserActivity
fix double alert on PostEditor -> MediaError notification
Merge pull request #262 from wordpress-mobile/issue-250

fix #250: show a VideoPress alert for WP.com blogs