Add more linear algebra tests

Fix a small bug in the .inv() method. While .inv() returned the correct
inverse, it did so with an additional column at index '-1'. Although the
other functions in the library ignored the '-1' column, the additional
column prevented equality comparisons. This has been fixed.

Reviewed-by: Trevor Norris <trev.norris@gmail.com>
Fix bug in gauss_elimination and add tests

Add tests for gaussian elimination function. Tests uncovered a bug; for
matricies of dimension greater than 3, the results of gauss_elimination
would always fail because of a problem in the back-substitution portion
of the algorithm. Bug has been fixed.

Reviewed-by: Trevor Norris <trev.norris@gmail.com>
Update built files
Working on patch 1.0.8