Updating unit test bootstrap

Now works with develop.svn.wordpress.org
Check alt. version post_parent ID before creating original

If post_parent = 0, $this->original was being set to the current global $post
Simplify method for retrieving alternate version for admin notices

Relies on post meta tracking key instead of alt. versions post_parent
Cuts out an unnecessary WP_Query
Adding checks for valid post properties before returning edit links

Without it `get_edit_post_link()` will misleadingly fall back to global $post
Be more robust inside of BU_Version::get()

Ensure that our internal $post and $original properties are correct
Version bump to 0.7.2