Fix option in MS_plot

Should be 'quiet' not 'silent'
Fix calculation of isorropic velocity

Rather than calculating the isotropic velcoty
from the isotropic component of the poly-xtal
anisotropic tensor (the norm of which changes
with texture) use simple VRH mean of the single
xtal tensor. This gives values that are just a
function of the temperature and do not vary with
texture.

Also split the velocity graph into two graphs.
Handle both the new and old file formats

Choose the format based on the first word
in the first line of the EBSD files. Data
is the same in both, but colomn order
changes.
Deal with non-vertical rays

These are still straight but have a inclination
that is not 90 degrees. Plot as a function of
source polrization (otherwise we end up with
chaos as we sweep around the azimuth) and
inclnation for different azimuths.

Some cleanup is needed.