resolve compilation issue of mcx_mie.cpp using MSVC

[ShijieYan]

No description provided.

[fangq]

a combination of 13679e9 and 6a9ad2f fixed the problem. now windows binaries are compiled.

windows build also detected these warnings, I believe gsmatrix was added in your patch

nvcc -c -g -lineinfo -Xcompiler -Wall -Xcompiler "/openmp /W0" -DSAVE_DETECTORS -use_fast_math -arch=sm_30 -DMCX_TARGET_NAME='"Fermi MCX"' -DUSE_ATOMIC -use_fast_math -DSAVE_DETECTORS -o mcx_core.obj  mcx_core.cu
mcx_core.cu
mcx\src\mcx_core.cu(2938) : warning C4701: potentially uninitialized local variable 'gsmatrix' used
mcx\src\mcx_core.cu(2938) : warning C4703: potentially uninitialized local pointer variable 'gsmatrix' used
mcx\src\mcx_core.cu(2866) : warning C4701: potentially uninitialized local variable 'updateprogress' used
mcx\src\mcx_core.cu(2866) : warning C4703: potentially uninitialized local pointer variable 'updateprogress' used