NE3: Addition of MKL third-party library

[robbmcleod]

NE3 relies on the GNU-standard library for most mathematical functions. These functions are inlined, but in general there are mathematical libraries available that are a solid 2-4x faster. One such library is the Intel MKL.

One disadvantage of Intel MKL is that it requires aligned arrays, so NumPy arrays that have been sliced will not work with it. E.g. newView = myData[:,:,-1] would work with LIB_STD but not LIB_MKL.
Another disadvantage of Intel MKL is that it requires a copyright license.