Run in viewport

[bitwes]

Add "Use Viewport" option which causes GUT to add GutTest instances to the viewport instead of itself. This means all calls to add_child in a test will be added in the viewport instead of on top of GUT. This fixes issue #121.

Adds additional options related to "Use Viewport"

• resolution: The resolution and window size that the GUT window uses. This defaults to the project settings. This does not affect the viewport size. The viewport size will use the project settings unless it is set. When the viewport is smaller than the resolution it will be right justified.
• viewport size: The size of the viewport. This defaults to the project settings. When this is smaller than the resolution it will be right justified.
• Gut on Top: Toggles whether the GUT Runner will be above or behind the viewport.
• Viewport Background Color: You can set a background color for the viewport. The default is transparent.