Merge pull request #23 from Tectu/master

Merge Tectu changes
Merge pull request #24 from Tectu/master

Merge Tectu Changes
Merge pull request #58 from inmarket/master

GWIN Slider plus other cleanups
Move demos to better locations
GWIN slider + image support
Merge pull request #25 from Tectu/master

Merge Tectu Changes
slider doc fix
Revert "slider doc fix"

This reverts commit c86cd58275c1efe62c6dd2f45e9996b077906352.
slider doc fix take one of two
Create generic GWIN Draw routine

For some GWIN controls they support a Draw() routine.
For those controls the base class now supports a generic Draw routine
which will call their specific Draw routine.
The only GWIN's with a Draw routine currently are Buttons and Sliders.
Merge pull request #59 from inmarket/master

Generic GWIN Draw routine
doc