Added code to handle_filter to enable/disable filters
added a button to the filter page to enable/disable filters
Added enable/disable filter button to the context page
This finishes up the last item mentioned in fedora-infra/fmn#13
Updated the icons for the disable/enable filter buttons to be a checkmark for enable, and an x for disable
Merge pull request #31 from rossdylan/disable_filter

Adding a Enable and Disable filter button