remove hardcoded 'build' string from path
remove hardcoded 'build' string from path

this allows for a more flexible way to specify
binaries location.

CVML/mexopencv,bearpaw/mexopencv,fengzhyuan/mexopencv,nanit/mexopencv,bearpaw/mexopencv,nanit/mexopencv,fengzhyuan/mexopencv,CVML/mexopencv