added new cmfd solver that doesnt require Petsc
added SOR
solver now works with coremap feature, loop is around rows now instead of i,j,k
default spectral radius is 0 (G-S no SOR)
added 1g solver and procedure pointer
can now set G-S tolerance, updated tests
added Wielandt shifting
added matrix copy and option to read in shift
added relative tolerancing and now can be set on input
removed copy of loss matrix for shift because we can overwrite loss matrix
updated cmfd test cases for tighter tolerances
cmfd shift cant be infinity due to FPE, making it very large and fixed matrix subtraction in solver
merged develop into cmfd_rbgs branch
merged develop into cmfd_rbgs
Merge branch 'develop' into cmfd_rbgs
Added capability to plot meshlines
Removed unused variable
Updated users guide for meshline plotting
Added commented-out example of meshline plotting
Added support for setting the color of a meshlines plot overlay