* introducing __all__ in modules, so __init__ imports only public objects;
* MultiTypeComboEntry renamed to ValidatedComboEntry and different data
type support implemented;
* ShortlistComboEntry introduced;
* ValueAction and ValueToolItem introduced;
* ComboToolAction and ComboToolItem are removed, ValueAction and
ToolComboEntry are implemented instead;
svn: r10763
4. Blow up 'grampswidgets' module into several smaller modules.
Also move 'objectentry' module out from 'widgets' to src/, otherwise there
would be circular dependency between the 'Editors' and 'widgets' packages.
svn: r10703
