Beautify Filter display

Fix #110 
Signed-off-by: Sheik Hassan <solergiga@yahoo.com>
There seems to be 2 methods of accessed being used. For example, above this line you do `attrs.value` and `attrs.operator` but on this line you are doing `this.model.get('field')`. I think everything should either reference `attrs.*` or `attrs` should be removed in favor of accessing via `this.model.get('...')`.