Improve jQuery UI integration

Brief analysis:
* The table wrapper needs to be classed with "ui-widget", or jQuery UI font settings will not apply. I hacked out a function injection at the $.fn.DataTable() level and add the class post-initialization. There may be a cleaner way to do this.
* I added a DataTable.ext.classes entry for sFilterInput, adding ui-corner-all.
* I created a new renderer.pageButton entry for jqueryui in the extension file. In this new renderer, page buttons are created as actual jQuery UI Button widgets and not just classed like them.
* I improved some of the stylesheet rules around the paging information and paging buttons. Several DataTables styles were overriding the jQuery UI theme. Additionally, the border radius for the paging buttons was not respecting jQuery UI corner styles.
* There seems to be no default oLanguage setting for oPaginate.sEllipsis. Currently I have this declared in the integration file.
* Might be several more things that I missed...