Delete class-wordpress-popular-posts-feed.php

The whole feed feature idea needs to be reworked. Will come back to it once WPP 3.0 is full stable.
Removes reference to feed class
Sets views update method to Ajax only to keep most bots out of the statistics
Removes unused variable from __update_views()
Adds About tab
Fixed transient bug
Adds MU check on data caching
Updates Shortcode API link
Updates plugin's main PO file
Updates spanish PO file
Updates german PO file
Removes Persian language since it's very outdated
Removes Dutch language since it's very outdated
Updates French language strings, a few are still missing/need updating
Updates Japanese language strings, a few are still missing/need updating
Updates plugin's POT file
Updates plugin's POT file