Modification of 'knc.h'

This is the modified version of 'knc.h' which produces 19 runfails and 662 compfails on ISPC test set.

However, if '__vec16_i1' is properly defined (i.e if the version with constructor is used) the 'knc.h' has 17 runfails and 411 compfails but has several additional compfails because of undefined overload of '__cast_uitofp' for '__vec16_i1'.

Please also take into account, that 64 bit gathers/scatters were changed to pass into icpc gather/scatter intrinsics 32 bit signed offsets. The previous version passed in an unsigned type, which sometimes produced segfaults.