Add numpy matrix operations support

[pedrohba1]

It would be interesting to implement some matrix operations such as:

    Lb = np.array(Lb) - ((numerand/pivot)* np.array(La)) 

[odashi]

@pedrohba1 Hi, thanks for proposing the issue!

It is somewhat unclear what is the desired LaTeX output of the given expression. So could you add some example outputs and/or behaviors too?

Ref: #38

[odashi]

Some features are taken over by other issues. Closes this issue for now.