update FindMemoryHoles howto
fix: rField_is... for RINGS
fix: test for make check in case Singular is not around
chg: separate omalloc and resources flags
chg: update factory version
chg: simplify jjTYPEOF
Merge pull request #535 from surface-smoothers/update.memoryholes.HOWTO

update FindMemoryHoles howto
Merge pull request #536 from mmklee/factory_noPP

Factory no pp
add: description for StringSetS/..StringEndS, SPrintStart/SPrintEnd
fix: attribute for newstruct (tr.585)