Adding new functions to SymPy vectors

[Rishabh Madan]

I would like to add an enhancement to sympy.vectors. We can have default functions for parametric representations of some basic surfaces like cylinders, spheres, cones etc.

Something like 

>>> cylinder1 = cylinder(Symbol('u'), Symbol('v'), Symbol('a'))

>>> pprint(cylinder1) 

>>> (a⋅cos(u)) N_i + (a⋅sin(u)) N_j + (v) N_k

Any opinions or thoughts about it?