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 
Not really. Just something I tried out to fix the hashing issue. Without any args, the <code>\_\_hash\_\_()</code> value comes out to be zero. Putting some args in, (see line 662), I get some non-zero hash value. Though that did not solve the issue.