sgemv cgemv pairs

part of PR #1993 that was inadvertently misplaced into the toplevel directory

from patch provided by aarnez in #991

from patch provided by aarnez in #991

from patch provided by aarnez in #991

as reported by aarnez in #1990

as suggested in #1990

* Tag arguments 0 and 1 as both input and output

* Tag arguments 0 and 1 as both input and output (see #1964)

* Tag operands 0 and 1 as both input and output

For #1964 (basically a continuation of coding problems first seen in #1292)

Fixed idamin,icamin choosing the first occurance index of equal minimals

casting ints is cheaper but it has a rounding, not memory casing effect, resulting in
invalid outcome

The dgemm_ncopy_8_skylakex.c code is not avx512 specific and gives
a nice performance boost for medium sized matrices

it's more efficient for certain tall/skinny matrices

sgemm_ncopy_4_skylakex.c uses SSE transpose operations where the
real perf win happens; this also works great for Haswell.

This gives double digit percentage gains on small and skinny matrices

with a few small changes it's possible to use the skylake sgemm code
also for haswell, this gives a modest gain (10% range) for smallish
matrixes but does wonders for very skinny matrixes