replaced Signed_Trait with make_signed
	modified:   M2/Macaulay2/e/aring-ffpack.hpp
	modified:   M2/Macaulay2/e/aring-gf.hpp
Merge branch 'master' of https://github.com/jakobkroeker/M2
build pari/gp binary when pari is enabled
Merge pull request #6 from jakobkroeker/master

get rid of signed trait in aring-ffpack