Rename coordinate classes to remove the "Coordinates" part
Changed docs to match new coordinates object names
updated What's new/CHANGES to reflect new coordinate class names
made AltAz more consistent with the new name
Add compatibility layer for old coordinate names
fix typo pointed out by @astrofrog
consistent imports across coordinates docs
further name fixes from rebase
Merge pull request #1614 from eteq/rename-coordinates

Rename coordinate classes, removing `Coordinates`