#39: More work on the math
#39: Implemented a little more math
#39: More math
#39: Added a constraint in the attribute listener for rotation to round to multiples of 90 and fire a warning when necessary.  I intend one day to implement arbitrary angles, but the sizer code for this is extremely difficult and the vast majority of uses for this will be at right angles.
Merge branch 'feature-BaseWidgets' into feature-Java8

Conflicts:
	projects/base/src/main/java/org/muis/base/widget/Transform.java
More project settings converted to Java 8