BDH additions bugfix, UPDATECHECK, DELETECHECK

1) made 	public function __construct() { PUBLIC so it can be called from elsewhere 
2) new function -----    function bikeindex_check_for_updates() -- checks BI API for bikes that have been updated, makes local update
3) new function -----    function bikeindexsync_check_for_deletes() -- checks BI API for bikes that need deleted from local blog
4) get_bikes_from_endpoint added ARSORT -- sorts from highest to lowest (newest bikes first)
5) changed: public function get_bikes_from_endpoint($force_past) {  to take the variable to force update-from-past 
-bhance
UPDATE DELETE admin changes

Admin side support for UPDATE DELETE SYNC etc
Merge branch 'bhance-patch-2' into september_improvements
slight tweaks, refactoring background class methods called from admin class
typo fix
Merge pull request #3 from purcebr/september_improvements

September improvements