Some updates and additions to the SAO sample

[jcward]

Playing with the SAO sample project, I found the edges to be a bit harsh, and the shadows dark and a bit ugly. Some tweaking could make it much prettier. So I:

• added an option to use the FXAA shader (on the color texture... I just copied what Pbr was doing, seems to work?)
• added options to control the shadows parameters
• reduced the default shadow power from 30 to 8, and quality from 0.5 to 1.0
• moved the vsync option from keyboard V to checkbox
• added keyboard shortcut hint
• added an option to make addSlider only display and set integer values (for samples and shadow size)

Before:

After:

[jcward]

Bump - any reason not to make the SAO example prettier / showcase more functionality? The only change to SampleApp.hx was to allow sliders the option to show only integers.