GridFilters - enhanced filtering for grids

[mjlecomte]

The original extension has been refactored for use with Ext 3.

This version has been checked into svn. I made a brief screencast, please click here to see it.

A few changes / enhancements to note:

1. each filter may be configured via the column model (less repetition of code)
2. the filter query format is configurable to use json format
3. filters will automatically reconfigure if the grid is reconfigured
4. filters clean up after themselves (there was no cleanup in previous version)
5. filter classes utilize form fields, so you can configure the fields to use validation for example
6. filters may be dynamically disabled from user manipulation (still experimental)
7. icons are modifiable just like any other menu and css (even with IE6 -- see attachment)
8. complete documentation, click here to see it.