Abaqus UMAT support

[ritukeshbharali]

Develop a AbaqusMaterial class that supports Abaqus UMATs. The idea is to compile them into shared libraries, and then load them dynamically. Here is the UMAT signature:

SUBROUTINE UMAT(STRESS,STATEV,DDSDDE,SSE,SPD,SCD,
     1           RPL,DDSDDT,DRPLDE,DRPLDT,
     2           STRAN,DSTRAN,TIME,DTIME,TEMP,DTEMP,PREDEF,
     2           DPRED,CMNAME,
     3           NDI,NSHR,NTENS,NSTATV,PROPS,NPROPS,COORDS,
     3           DROT,PNEWDT,
     4           CELENT,DFGRD0,DFGRD1,NOEL,NPT,
     5           LAYER,KSPT,KSTEP,KINC)

It uses insane many variables, so to make it truly generic, the AbaqusMaterial must have these variables are members. For a basic example, see https://github.com/ritukeshbharali/Abaqus-UMAT-cpp.