BibEdit: HoldingPen multiple improvements

• Add hide preview button of HP changeset preview on top.

• When clicking on a HP change div, avoid opening the cell for editing.

• Algorithm does not compare any more the fields according to the sequence they appear , but better according to their content.

• Send all queued requests before apply/reject all

• Removes menu buttons and added fields from view when user switches to Text Marc mode.

• Documentation and refactoring of comparison algorithm related functions.

• Increase size of div containing changeset buttons

Reviewed-by: Javier Martin Montull <javier.martin.montull@cern.ch>

BibEdit: fix Firefox's window.event bug

• Firefox does not have the resctricted keyword event, as Chrome/IE do. Adapt code to work on Firefox.