docs: cleanup coordinates import (from astropy import coordinates) and
use 0.4-style coordinate declaration.
Also, added a new index of services by type
NED is also an archive service
docs: rst, coordinate import cleanup
docs: title level consistency
docs: remove some trailing spaces and reorg ogle's title styles
docs: headings in __init__ files are apparently necessary in *some* but
not all cases
docs for classes - NED (I think this may have been the cause of the
inconsistent title error before - classes need docstrings)
docs: conf.py -> mock out bs4
docs: sections -> chapters in failing regions
sphinx doesn't like tildes
Merge pull request #356 from keflavich/docs_0.4

Docs: Minor fixes, especially formatting