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 changed it to this, but the tests fail now.
  ` x = np.arctan(-np.cos(lamda2) * np.tan(ob1))
    y = np.arctan(-np.cos(diff) * np.tan(i))
    result = x + y
    return Angle(result.to(u.deg))`