The MathView now draws an empty box when there is no MathObject associated with it

Signed-off-by: Mark Kamsma <mark@markkamsma.nl>
Repackaged all classes in a useful hierachy.
minor bugfix with the calculating of divides
Offset handling fix
Merge branch 'master' into work
Logical line remodeld
Deletete zelf maar
Fixed the lasting bug of the 'moving' quotients
Merge branch 'drag-and-drop' of https://github.com/Divendo/math-dragon

Conflicts:
	src/org/teaminfty/math_dragon/FragmentMainScreen.java
	src/org/teaminfty/math_dragon/MathShadow.java
	src/org/teaminfty/math_dragon/MathView.java
	src/org/teaminfty/math_dragon/view/MathSourceView.java