Better handle on negative lubrication height and zero element volume

This pull request is to better handling lubrication height and zero detJ. Before, this was done with EH and it halts the calculation. Now, they are handled in similar manner as negative detJ in mesh equation: Under-relax Newton's method in steady state problem or decrease time step in transient problem
As I just mentioned to Weston, having global variable flags that are carried around everywhere is very poor programming practice.  I know we do it everywhere in Goma, but it would be great if we could stop doing that.  I'll go ahead and accept the pull request, but I'd like it if you could find a way to do this a bit more gracefully.  A singleton that has getters and setters might be a better choice?