Allow time step to increase after shrinking.

This addresses issue #3764.
small style modifications refs #3765 #3764
Add test for regrowing DT with ConstantDT refs #3765 #3764
Pruning submodule directories
closes #3853
Skip thermal term in J if material property for it doesn't exist ref #3807

This fixes a test we inadvertently broke in Marmot.
Merge pull request #3855 from friedmud/constantDtRegrow_3764

Constant dt regrow
Merge pull request #3854 from permcody/prune

Pruning submodule directories
Merge pull request #3856 from bwspenc/j_thermal_term

Skip thermal term in J if material property for it doesn't exist