fixed RectangleButtonSpecs, updated Screen trait
updated Shell
began work on basic Real type
did more work on basicReal
Merge remote-tracking branch 'origin/develop-SN' into develop-JK
Merge remote-tracking branch 'origin/develop-MW' into develop-JK
fixed Specs
fixed Specs, separated Shape/ShapeElement, added Rectangle, Ellipse, Circle
Merge remote-tracking branch 'origin/develop-JK' into develop-SN
openGL draw rectangle