Rewrites documentation for rotate3_inertia and renames to relevant functions.

The rotate3_inertia's documentation defined the rotation matrix as v_a = R *
v_b but what it actually returned seemed to be from the definition v_b = R *
v_a. I updated the documentation to reflect this and altered the
Human.inertia_transformed to return what it's documentation says it returns.
Finally I renamed rotate3_inertia to rotate_inertia and switched the order of
the arguments and I renamed Human.inertia_transformed to
Human.transform_inertia so that the name is a verb indicating what the method
does rather than what it returns. Both of these have deprecation warnings so
the old names can be used until Yeadon 2.0. I also moved the deprecation
warning to it's own module so that it can be more easily used in all the
modules with no chance of circular dependencies.
Changes rotate3_inertia to the definition assumed in solid.py and segment.py.

rotate3_inertia was defined expecting the rotation matrix, R, to transform a
vector expressed in the unrotated frame, A, into the rotated frame, B (i.e. v_b
= R * v_a). But this was being used in the calc_properties methods in solid.py
and segemnt.py incorrectly. All of the rotation matrices formed in human.py and
passed to the segment definitions use R defined as v_a = R * v_b. So we were
incorrectly computing rotated inertia values. This remedies that but now there
are broken regression tests based on previously computed inertia values. These
tests will need to be updated to reflect the new computed values.
Merge pull request #80 from chrisdembia/try-transpose

Changed the definition of the rotate3_inertia function.