replace factory by a recent version from Singular github snapshot
factory now depends hard on ntl and gftable file names changed
libfac_version is now defined in a header and not as a symbol.
replaced factory's initializeGMP with a dummy
removed unnecessary patch
fix a test
patch no longer necessary (is empty)
update check for gftables presence
starting to fix pull/126, which initiates the use of version 4 of factory+libfac
fixing pull/126, part 2
fixing pull/126, part 3
fixing pull/126, part 3; a flint test needs a lot of memory
fixing pull/126, part 4
start adapting release of factory 4.0.0

The problem solved was that it didn't include the needed m4
macros.

Wait for libfac 4.0.0 to be released.
fixing pull/126, part 4; disable some slow FLINT tests
Merge branch 'pull/126' of github.com:DanGrayson/M2 into pull/126
fixing pull/126, part 5; improve check-configure makefile
update libgc to latest version 7.4.0
update program Normaliz to version 2.11.1
add link to homepage for normaliz
update configure test for gc

Version 7.4.0 doesn't define GC_version if just a sharable library is built, so
switch to using the newer macros GC_VERSION_MAJOR, GC_VERSION_MINOR,
and GC_VERSION_MICRO.

Fixes #130.
fixing pull/126, part 6

the latest factory factors polynomials in a different order,
so we fix a test