Need to provide an easy-to-use mechanism to prevent ICEfaces app. users from sending multiple submits/partialSubmits to the server concurrently as this can cause application and/or user UI issues with some applications.

This can be provided by adding an optional feature to the bridge that would perform the following:

- As a call to submitFull() or submitPartial() is made the bridge will:
   1. Set the cursor/pointer to an hourglass
   2. Display a semi-transparent DIV over the current application UI, similar to the technique used by the modal dialog, but less opaque. The intention is to provide a subtle visual indication that the application is busy and also to prevent user interaction with the application via mouse.

- Once a response for the submit is received (or timed out, etc):
   1. Remove/hide the semi-transparent DIV.
   2. Restore the cursor/pointer to it's original shape (or to a pointer if that's impossible).


This feature can be enabled via a new config. param "com.icesoft.faces.blockUIWhenBusy", or maybe "com.icesoft.faces.blockUIOnSubmit".