Integration of astropy.units in sunpy codebase

Attempt to integrate the astropy.units into sunpy. Every function that were taking or giving a quantity now must have astropy quantity associated with them. Please tell me if I have made mistakes anywhere, or if it could be done in better way, I will make changes! 
Thank you!   
I think you could delete the whole file... but as it's now Travis fails tryting to find the the two fucntions deleted `degrees_to_hours()` and `degrees_to_arc()` because they are mentioned in `__all__`