Manage w2p:enable-with in order to reuse form

The current situation doesn't allows a simple html form to be reused. 
The submit of a single form (ajax submit) fires several activities which all managed the variable el.data('w2p:enable-with'). Namely, disableElement is called two times, and one time is called disableFormElements.

Due to those several calls the value of el.data('w2p:enable-with') is initially and correctly set to the value of the element but then is re-set to 'working ...' because this latter is the value of the element. When you call enableElement you will find in el.data('w2p:enable-with')  'working ...' instead of the right one.

@niphlod do you agree?