Make pyfits an optional dependancy with astropy.io.fits first
Build deps and setup.py changed from pyfits to astropy
Merge remote-tracking branch 'upstream/staging' into pyfits

Conflicts:
	.travis.yml
	setup.py
Merge pull request #489 from ehsteve/map

A few bug fix for refactor and plotting
Fix fails due to pyfits.core
Merge pull request #488 from Cadair/pyfits

Deprecate pyfits in place of astropy
Fix behaviour when DummyAttrs remain in query.
Fix missing EOL.
Remove DummyAttr from HEK walker.
Add tests for HEK.
Make spectrogram plotting consistent.

Lacks updated docs!
Add download progress bar.
Fix downloader deadlock.
Fix refactor regression.

clip_freqs no longer updated the freq axis.
Update docs.
Fix tests.
Improve tests
Add a word about Anaconda.
Add word about multiple Python envs.
No longer leak fds.