Added MeshTopologyTests to runTests.  (These complement, rather than replace, the tests in DPGTests.)
Corrected comment.
Changed various default settings vis-a-vis command line.
Refactored MeshTopology and Cell to reduce memory footprint.  Added mechanisms for estimating the memory footprint of MeshTopology and Cell.  There is more low-hanging fruit to reduce memory footprint; at this point, for my test 2D mesh, it's been reduced by a factor of about 2.