added filter field.

Added a field to allow users to apply custom filter to collection.

I have tried to follow the global mongs coding style but I have moved the script and styling in standalone files.

I have verified the gui on firefox and chrome on my computer (kubuntu 13.04) and it looks fine.  I can still rework the styling to make it nicer (even if I am not really good differentiating the nice of the ugly).

Fell free to deny this poll requests if the code quality is not hight enough.  I am willing to re-work on it if required.

didiercrunch