Make "Save Draft" on leaving the editor actually save a draft

git-svn-id: http://ios.svn.wordpress.org/trunk@4018 7d847f7c-ffe1-4a24-85be-b788d016d96a
Added new WPFLogMethodParam helper function

git-svn-id: http://ios.svn.wordpress.org/trunk@4019 7d847f7c-ffe1-4a24-85be-b788d016d96a
Better post previews

* Added autosave logic, so unpublished posts can get autosaved remotely
* If online, autosave drafts and show a real preview
* If the post is already published or we're offline, keep showing the simple preview

git-svn-id: http://ios.svn.wordpress.org/trunk@4020 7d847f7c-ffe1-4a24-85be-b788d016d96a
Implement better previews for pages

git-svn-id: http://ios.svn.wordpress.org/trunk@4021 7d847f7c-ffe1-4a24-85be-b788d016d96a
Refactor simple previews loading

git-svn-id: http://ios.svn.wordpress.org/trunk@4022 7d847f7c-ffe1-4a24-85be-b788d016d96a