Check for null in the html string before matching the RSD link. Fixes #400. props willnorris

git-svn-id: https://android.svn.wordpress.org/trunk@881 a6565c4b-a94d-4d28-bb26-aa9e5ab542c0
Fixes authorization failed prompt, and added more helpful error messages for failed post uploads. Also added a few strings and fixed a spelling error ;) Fixes #401

git-svn-id: https://android.svn.wordpress.org/trunk@882 a6565c4b-a94d-4d28-bb26-aa9e5ab542c0
More helpful messaging if the user has exceeded the login limit.

git-svn-id: https://android.svn.wordpress.org/trunk@883 a6565c4b-a94d-4d28-bb26-aa9e5ab542c0