Mai & Anoop: Story 1126: rename Field.enabled to Field.visible

Hi JR,

This is the implementation for story #1126
We have renamed the field "enabled" to "visible" for "Field".

Not sure if we need to do the same for "FormSection" or not since the story only mentioned "Field", but same issue exists in FormSection as well. Can you clarify if we should continue renaming the filed in FormSection as well?

Thanks
-- Mai & Anoop