Update all Rochester linear algebra problems and many TCNJ linear algebra problems to MathObjects
Change display_matrix to display_matrix_mm wherever feasible in Rochester problems and otherwise upgrade to MathObjects or update display to use LaTeX
Merge pull request #79 from paultpearson/master

Update linear algebra problems (Rochester=all and TCNJ=many) to MathObjects.

I thought I had seen it in the Files Changed link, but cannot find it now, so I guess I was mistaken.