Added UnexpectedVectorConversionException

Added UnexpectedVectorConversionException for when the toVec3 or toVec4
method is called on a Matrix that cannot comply. Also added the code for
LinearSystemSolver to catch the exception and for Matrix to throw it.
Also added a wee bit of extra error handling to the Matrix's
constructors.
Set state to null in constructor.
Created Test classes

Created test classes for testing the Menu, MenuStates, LinearSolver and
Interpreter.
Implemented Matrix Tester

For testing the Matrix class.
Merge branch 'development' of https://github.com/Threepud/Sketchup-Blocks into development