Improved the core datatype factory base class and updated MapFactory to
use the new version.
Merge branch 'master' into factory_update

Conflicts:
	sunpy/map/map_factory.py
	sunpy/util/datatype_factory_base.py
Add vso.attrs module to the api docs
Fix the documentation warning by removing the manual Methods section
Merge pull request #1 from Cadair/map_factory_update

Fix the documentation warning by removing the manual Methods section
added a test for empty databases in display_entries
Merge pull request #751 from derdon/dbtest-display_entries

added a test for empty databases in display_entries
small tweaks to coverage and test output
revert tweak to table print
Merge pull request #753 from Cadair/testing_tweaks

small tweaks to coverage and test output
Merge pull request #729 from rhewett/factory_update

Improved the core datatype factory base class and updated MapFactory to use new version.
Merge pull request #749 from Cadair/vso_docs

Add vso.attrs module to the api docs