Remove less accurate/computationally stable angular distances
Rename vincenty... to angular_separation, update documentation
Expand spherical distance tests to include float, quantity, angle
Correction to separation docstring that caused sphinx build failurs
Remove reference to non-public routines in documentation.
Retry separation docstring, as it still gives errors
Remove leftover doc reference to AngularSeparation class
Merge pull request #1428 from taldcroft/fix-separations-doc

Remove leftover doc reference to AngularSeparation class
Merge pull request #1397 from mhvk/coordinates-remove-dist-approximations

Remove less accurate/computationally stable angular distances
Ensure Angle subclass is conserved when changing unit
Ensure wrap_angle is passed on for Longitude (and equivalencies)
Remove unit setting in wrap_angle setter; explicit tuple elsewhere.
Merge pull request #1423 from mhvk/angles-ensure-subclass-is-kept

Ensure Angle subclass is conserved when changing unit
Support Unicode "MINUS SIGN" (U2212) in Angle parser.
Output Unicode MINUS SIGN in Unit unicode formatter