draw facade watermark only in DEBUG
added row_label spec to grid (string format or empty to hide)
fixed handling of dicts in GridModel (GridRow creation)
changed to grid method to hide labels compatible with wx2.8
replaced data_selection by value and string_selection by text in item container controls
reintroduced text spec in text box
fire a selection event if selection has changed programmatically), unified internal methods (item container controls)
fixed None support on text box for dates (workaround for exception: invalid null reference in method 'DatePickerCtrlBase_SetValue', expected argument 2 of type 'wxDateTime const &'
fixed grid event detail
added format and choices specs to grid view
convert choices to internal representation in grid
renamed col grid event attribute
added combo cell editor (using choice and custom implementation)
avoid error if subitem not in choices (grid)