Added option of using previous steps strain rate to soften materials, updated only at the end of the previous step

Added option of defining a dominant material type that will define the element material properties if any volume is present within an element

Replaced ztrans functionality for material transitions below a given depth to a more general transition behavior which allows transitions in at any constant x, y or z value

Added output of yield_ratio and did minor cleanup; moved ziso stuff into bc_definition derived data type

Added Jean's subroutine for moving surface points along a normal to coincide with the zero of the LSFs

Added integer 'matnum' (material number) to osolve. Added logical 'nest' to parameters. Cleaned up a bit.