fixup type names for Upper and Lower, along with Unit NonUnit.
cleanup related to supporting testing more easily
elaborate some comments / docs  more in the MatrixTypes more
kill notion of "reference blas"
add basic unit testing for operations.

Unit tests are on inputs sizes and matrix values chosen so that the
results of the computations can be treated as being exact.

Unit tests that handle questions of numerical precision / stability are a future project, but
ignore for now in basic test suite