chg: updated README for 4.0
rm: old GNUmakefile
chg: added FLINT to Singular doc preface
chg: added my name to factory copyright in Singular doc preface
rm: FACTORY.INSTALL (README should be sufficient)
chg: changed version to 4-0 in copying
moved FLINT to non optional part in manual preface
fix french accent aigu
Merge pull request #411 from mmklee/factory40

Factory40
fix: convert ptr to int via intptr_t
fix: stdint.h is needed on some systems for intptr_t
fix: typo
chg: structs.h again usable for C and C++
Fix BS problem of gfanlib handling