...not a matrix size. For GEMM_MULTITHREAD_THRESHOLD=4
(the default value) this does not change anything but
for other values it make the GEMM and GEMV thresholds
changing in the same way.

Close #742

The ones given in 3ae30cd was by far to low because I
mixed m and m*n in my measures. Note that the new ones
are closed to the [z]gemv ones which is comforting
that both are right.

Ref #730: added performance updates for syrk and syr2k

BENCH: Minor fixes in SciPy benchmarks

Bug731

Close #731

Ref #731

Fixes for old outstanding bugs in CBLAS test programs

The NTRA argument can be equal to -1 if one does not want a snapshot file
(and this is the case with sample data {s,d,c,z}in3).
The routines {S,D,C,Z}PRCN3 will try to use their first argument as an output
unit number, so we avoid calling them when NTRA < 0.

Patch originally written by Camm Maguire.

The SNAME variable contains names of C functions like "cblas_dgemv".
Apparently the code was not taking into account the 6-letter "cblas_"
prefix when determining the task to be done.

The issue does not affect c_{s,d,c}blat2.f, which use the correct
offsetting.

Patch originally written by Camm Maguire.

* Fix commit 87a2ccc
* Close #736