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!   
Also, I think if the equation contains a quantity, the result would be a quantity... so this could be producing adding units to something it has already.  In fact, the function above may give radians, so the right way to do this would be:
```python
result.to(u.deg)
```
or nothing, because Latitude would use it properly.