moved out of class operator+() and operator-()
removed predeclaration for haveSameSize
added template typename VALUE_TYPE to template operator* and added it's predeclaration
changed logic of operator-() to make it more simple
removed FRIEND_TEST(MatrixIsMultiplyPossible, AllCasesWithVector);
moved unary operator-() out of class Matrix
moved operator==() out of class Matrix
added function transpose()
added TEST(Transpose, Matrix1x2)
added TEST(Transpose, Matrix2x2)
added TEST(Transpose, Matrix4x4)