Use `\overset{\circ}A` for Angstrom LaTeX.
Allow float, int, long of any dimensionless quantity, even if not unscaled
Update documentation to reflect that all dimensionless scalars can be converted
Add changelog entry in API change section
Updated CHANGES.rst
Merge pull request #2286 from mdboom/unit/angstrom with manual merge

Added CHANGES.rst entry
Remove Quantity.__eq__, __ne__ so that == and != always return True, False
Add extra test, entry in backwards-incompatible changes
Tighten up test that __eq__, __ne__ really return True, False
for units that cannot be converted
Merge pull request #2328 from mhvk/quantity-equality

Remove Quantity.__eq__, __ne__ so that == and != always return True, False
Merge pull request #2249 from mhvk/quantity-float-int-long

math functions don't decompose quantities correctly