v2.0 beta Full rewrite

This release includes the following

• complete re-write of the plugin file structure.
• removal of custom DB table, post rank is now saved as a postmeta key.
• addition of a new filter 'reorder_post_within_categories_new_post_first' to allow new posts to be ranked first instead of last by default.
• proper handling of post_type for order ranking.
• ability to reset/delete data from settings page.