Post model cleanup:

 * Removed all database work from the Post model.
 * Added new WordPressDB method to return a post with a localTablePostId.
 * Corrected variable naming in post model (camelCase) and their getters/setters.
 * Removed old migrateDrafts method from WordPressDB.
Merge branch 'develop' into issue/968-load-post-fixes

Conflicts:
	src/org/wordpress/android/ui/posts/PostsActivity.java
Added some basic Post tests, fixed up tests that used old method of loading/creating Posts.
Fixes test from not running. props @maxme
 * Removed save, update and delete methods from Post model, instead call the db methods when performing CRUD operations.

 * Fixed some null checks to use TextUtils.isEmpty.
Cleaned up the getMediaFile method.
Fixed EditPostTest.
Merge branch 'develop' into issue/968-load-post-fixes

Conflicts:
	src/org/wordpress/android/ui/posts/PostsActivity.java
	src/org/wordpress/android/ui/posts/PostsListFragment.java
Adding missing 'more text' when loading a post from the DB
Repositioning more text load to make more contextual sense.
Checked for Post model String getters that were still checking for null. Some of the checks I didn't replace with TextUtils.isEmpty() because a user may have wanted to empty out a field, such as post excerpt or keywords.
Added notNullStr wrapper to getQuickPostType to be consistent with other string getters in the Post model.
Removing an extra line.
Merge pull request #1080 from wordpress-mobile/issue/968-load-post-fixes

Post model cleanup