fixed a couple of warnings
created HoudiniSolveTermination for terminating solve in houdini!
added some checks to conjugate residuals solver
updated sconstruct
added some file types to .gitignore
added some nan checks, plus fixed infinite hardening problem
Merge branch 'master' of https://github.com/davidsminor/mpmsnow

Conflicts:
	src/MpmSim/Sim.cpp