Bugfixes and default theme changes.

Fixed Default theme.
Fixed highlights bugs in Input, Menu, Button, Checkbox widgets when used
in a scrollable parent. (inspect.stack() is very useful)
Removing TransparentFrame -> use GuiFrame without graphics to use a
transparent dialog.
fixed editor and code refactoring.

fixed highlight bug in checkbox.py
fixed bug in ToggleImageButton when using ToggleGroup.
Added new example "example_basic1"
added 'restricted' option in 'Input' widget to restrict characters set.