OOIION-1628
Complete rehaul of datatables filter. Now everything works as advertised. You can apply > 1 filter to individual columns, and each operation works (contains, greater, less, etc.). For the record, everything is compared as strings, but datetime comparisons work fine becuase they are yyyy-mm-dd... . Also, I'm not sure why GREATER THAN and NEWER THAN (as well as LESS and OLDER) are options since they do the same thing.
Merge pull request #280 from cgalvarino/fix_filter-r2

OOIION-1628