added jacobians to low mach navier stokes; need cleanup and consistency check; also needs d_mu/dT
Cleaned up code; added d_rho function to lmns_base.h; also precomputed some repeated term; still need to tackle d_mu, d_k, d_cp;
Created new example test 3D analytic Jacobinas for LMNS.C, and added to Makefile and configure.ac; redid naming conventions for repeated terms in LMNS.C; added myself to AUTHORS
Fixed bug in LMNS.C; added 3 tests for simple convection cell in 3 different directions to test analytical Jacobian components; changed cavity_benchmark_no_stab.in to make example better
Altered 3d_low_mach tests to use input file from top_srcdir, instead of having those in the top_builddir; modified configure.ac to reflect this
Merge pull request #183 from tradowsk/jacobians

LowMachNavierStokes Jacobians from Master