Linear Algebra Module

According to the discussions I had with Ondrej, this PR provide the basic prototype for the Matrices in Linear Algebra Module. This is not final and subject to change after the discussions. Basic to-dos are as follows.

### TODO
- [ ] Decide on the storage of Sparse Matrices. We have a lot of methods available in this [wiki page](http://en.wikipedia.org/wiki/Sparse_matrix#Storing_a_sparse_matrix). All most all of them are implemented in `scipy.sparse`.
- [ ] Decide if we follow an approach similar to LELA or LinBox which will provide a more mathematical way of doing things related to Matrices. Ondrej idea was to wait till we get the basic functionalities ready and do this afterwards.
- [ ] Add tests