command should not be aliased to control by default

HTML/XML export now single menu entry * added keyboard shortcuts for print/save * display dialog when export encounters error

Remove string module use from external modules.

Further removal of string module from core.

No need for string module now.

Clean up deprecated code: exceptions.Exception, new.instancemethod.

Restore Fernando's fix for the __del__ methods on exit bug.

Make test work (i.e. it now fails, as expected).

allow any file extension

html export fixes