Removed old Mex command implementations

src/c/Mex/MexClosure.cpp

src/c/Mex/MexCommand.cpp

src/c/Mex/MexCommand.h

src/c/Mex/MexDeviceCount.cpp

src/c/Mex/MexDeviceStats.cpp

src/c/Mex/MexElementWiseDifference.cpp

src/c/Mex/MexEntropyFilter.cpp

src/c/Mex/MexGaussian.cpp

src/c/Mex/MexGetMinMax.cpp

src/c/Mex/MexHighPassFilter.cpp

src/c/Mex/MexIdentityFilter.cpp

src/c/Mex/MexKernel.cpp

src/c/Mex/MexKernel.h

src/c/Mex/MexLoG.cpp

src/c/Mex/MexMaxFilter.cpp

src/c/Mex/MexMeanFilter.cpp

src/c/Mex/MexMedianFilter.cpp

src/c/Mex/MexMinFilter.cpp

src/c/Mex/MexMultiplySum.cpp

src/c/Mex/MexOpener.cpp