Add LLA2NED function and placeholder for a test.

This functino wraps existing tools.  Namely, LLA2ECEF and ECEF2NED.
Remove function 'euler2tilt_errors' and associated test.

As per decision that this was not a general function and hence not
suitable for NavPy.
Remove Rbody2nav_to_angle and associated test.

This method would techincally be accomplishable using a wrapper
around dcm2angle.  Since it is not general, it will be removed.
Update navpy to use former nav omega2rates function.
Updated associated tests.
Added argument to specify output type ('matrix' or 'ndarray').
Correct syntax bug in lla2ned.
Add (passing) test for lla2ned.
Migrate test for angle2dcm from nav to navpy.
Merge branch 'master' of https://github.com/NavPy/NavPy into func_dev

Conflicts:
	nav.py
Remove dependency on old file (nav.py).