begin velocity functions unit tests
Merge branch 'master' into vel
Merge branch 'master' into vel

Conflicts:
	ion_functions/data/test/test_generic_functions.py

fixed pull request 17 merge conflicts, and updated
Re-wrapped the vel functions.  Fixed test_vel filename.  Other fixes.
Fixed vel_functions
Merge branch 'master' into vel
Merge branch 'master' into vel
Merge pull request #18 from s-pearce/vel

Vel