Pygubu

* Property editors rewritten from scratch
* Improved menu preview
* Added font property editor
* Fixed menu issues

* Add select hotkey to widget tree. (i - select previous item, k - select next item)
* Copied menu example from wiki to examples folder.

* Renamed designer startup script to pygubu-designer (see [20](/../../issues/20))
* Fixed bugs.

* Added Toplevel widget
* Added generic Dialog widget
* Rewrited scrolledframe widget internals, ideas and code taken from tkinter wiki.
* Added more widget icons.
* Fixed bugs.

* Allow to select control variable type
* Fixed some bugs.

* Added more wiki pages.
* Fixed issues 3, 4