Added tests for many of the linear algebra functions.

Additionally, fixed a small bug that prevented .dot() and .angle() from
being called on a jStat object, as opposed to as a static function.

There are still untested functions in the linear algebra library,
and it does not make sense that all of the linear algebra functions
can be called on a jStat() object but only accept plain matricies
as arguments. This future change will be made easier with fuller test
coverage.