Preparing branch for v0.4.1.
Adding skeletons to changelog for next releases.

Conflicts:

	CHANGES.rst
Merge pull request #2623
Merge pull request #2742 from larrybradley/patch-1

Update matchsep.rst
Merge pull request #2728 from jehturner/patch-1

A few short docstrings in examples for issue #1414
Merge pull request #2722 from jeanconn/add_flymake_cursor

Add link to flymake-cursor.el in Emacs dev docs
Merge pull request #2754 from mdboom/wcs/memleak

WCS memory leak
Merge pull request #1419 from mhvk/quantity-init-with-objects

Cannot create Angle objects with decimal.Decimal
Merge pull request #2697 from cgohlke/patch-2

Fix integer overflow in np.product
Merge pull request #2261 from mhvk/distance-lists-ok

Distance should accept lists of quantities with different units
Merge pull request #2760 from astrofrog/more-known-issues

Expand locale known issue
Merge pull request #2763 from mdboom/wcs/bounds-check-doc

astropy.wcs returns nan when galactic longitude >= 180 degrees
Merge pull request #2764 from mdboom/docs/latex-fixes

LaTeX doc build fixes
Merge pull request #2775 from mdboom/wcs/use-astropy-helpers

Use astropy_helpers for setup_helpers in wcs test_api_extension
Merge pull request #2777 from mdboom/wcs/mention-all_world2pix

missing mention of all_world2pix method
Merge pull request #2718 from mhvk/quantity-output-wrong-unit

Ensure in-place ops on Angles with non-angle result do not corrupt the instance
Merge pull request #2652 from adonath/fix_for_#2174

Fixed kernel multiplication with  numpy floats #2174
Merge pull request #2772 from mdboom/config/issue-2772

Configuration warnings with clean 0.3.2 -> 0.4 upgrade
Merge pull request #2727 from eteq/deprecate-cartesianpoints

Deprecate (and fix) CartesianPoints
Merge pull request #2798 from mdboom/unit/obscure-roundtrip

Originally valid FITS unit cannot be formatted