New grid multioptions filter

I've recently ported and adapted to use jQuery quite interesting grid filter (see attached screenshot). It allows you to search for records that have one of selected values in given column.

For example it allows you too show users that have "Active or Pending" statuses. Before that filter we were able to select only one value at a time, e.g. only show "Active" or only show "Pending", but not together.

Screenshot details:

1. show filter in dormant state
2. show filter, once it's clicked by user

Patch for 5.1.0 and later versions only.

To use, you must set "grid_multioptions_filter" to any column in grid, that has "kOptionsFormatter".