Renamed libxsmm_util.h into libxsmm_knc.h (because it's KNC specific).
Avoid leading underscores for user-defined functions.
Fixed generator scripts load_dims function to actually return a sorted list (needed when dispatching a function using binary search). Specify code paths mainly for the host side (Makefile); use generic SSE3 as a baseline and Intel AVX2 for multi-versioned code. Wrapped up mangling symbols on a per-function basis (LIBXSMM_EXTERN_C macro). Reworked the library's interface and added an interface specific for C++. Updated README.md according to interface changes.