Size: The default formatNumber method has been reduced in size.

- Exactly the same functionality, but now uses a regex to perform the
  same operation
Fix: Add support for the `input`, `paste` and `cut` events in the filter input

- IE10 has a little `x` to clear text boxes which fires the `input`
  event, so we need to monitor for that in the filtering input.

- While I'm here, I've also added support for the paste and cut events
  to change the filtering when they fire. Via keyboard the fire on
  keyup, but not if you use the mouse. They do now.

- Not that it us possible to have multiple events fire (keyup + paste
  for example). The logic of checking for a change of input counters
  this.

- Thhis fixes DataTables/DataTables issue #227.