Basic Vector framework

Added:

1. Vector core - Vector, VectorAdd, VectorMul, BaseVector
2. BaseScalar
3. Del
4. CoordSysRect
5. Point
6. functions.py - express, matrix_to_vector 
I have pulled in orient_new's docstrings to this one's. Plus, doing <code>help(CoordSysCartesian)</code> now prints all the docstrings of <code>\_\_new\_\_</code> and <code>orient_new</code>