Thread safety tester using C++11 threading (cleaned history)

for #2151

for calling from concurrent threads

Found via `codespell -q 3 -w -L ith,als,dum,nd,amin,nto,wis,ba -S ./relapack,./kernel,./lapack-netlib`

as suggested in #2022

add note about NUM_THREADS for package maintainers, add examples of programs that cause affinity troubles

Revert generate to install, explain the nature of the affinity conflict

Lots of small changes in the wording of the comments, plus an expansion of the NUM_THREADS and NO_AFFINITY sections.

* Document the stub status of the QUAD_PRECiSION code inherited from GotoBLAS2

in response to #1769

* Allow choosing the OpenMP scheduler and add range hint for GEMM_MULTITHREAD_THRESHOLD
* Amended description of GEMM_MULTITHREAD_THRESHOLD
to reflect #742 making it track floating point operations rather than matrix size

Change-Id: Ic896276cd073d6b41930c7c5a29d66348cd1725d

This setting must have been changed unintentionally by my PR #1214 (probably leftover from unrelated tests)

* Disable ReLAPACK by default; mention it in final build message if included

* Add files via upload

* Add files via upload

* Add files via upload

Close #828 (hopefully)

Bump to 0.2.18.dev

Conflicts:
	CMakeLists.txt
	Makefile.rule