fix to restore multithreaded internal ecm

needed to re-include a header when ECM = 1
added updated ggnfs binaries for windows (with keep_afb changes)
added siqsbench fix for qs_demo

Merge pull request #90 from kyleaskine/feature/afb-validation-checks

Enhancements to algebraic factor base files

+ attempt to fix builds failing on linux with clang due to undeclared…

… nice() function

move the suppression of auto-vectorization to the base cflags list in…

…stead of just windows.

change to installer-url instead of release date

+ a couple more PRIu64 in gmp_printf changes.

+ check for non zero a-polys before freeing it.

fix long/int incompatible pointer types

mingw poly select now works (still seems slower than linux, but at le…

…ast it's functional).

remove "initializing tlevels" message
always use new sizeopt callbacks (todo: gather data on the different methods)
suppress "crap" messages and instead just count them (report once at the end)

Update yafu.h

prepare new tag to auto re-release with new fixes.

Update build-linux.yml

using find to resolve multi-arch gmp install location