Fix code for cholmod < 2.1.

It is field IPerm which was added in cholmod 2.1, not field Perm.
improve array intersect/union. fixes #4725
improve type of set union
quick hack to fix #4715
fix #4688, inlining too early inside method definitions
Fix #4723
Don't compute factorization twice

See #4732 and d46936bcc9a55ea184f3420ef900ba7f9ccc83b9. Ugh.
Merge pull request #4721 from sebastien-villemot/master

Fix code for cholmod < 2.1.
fix bug in function name in some line number nodes

ref #4716
typo: regsitered --> registered
Merge pull request #4732 from waldir/patch-1

typo: regsitered --> registered
in init_stdio, get FD out of the file object instead of hard-coding it
Merge pull request #4734 from JuliaLang/jb/fixstdfd

in init_stdio, get FD out of the file object instead of hard-coding it
correct a number of over-specified function types in intfuncs
Revert "correct a number of over-specified function types in intfuncs"

This reverts commit 3ddc69966c9501b1ddec6c090d27a40ffddf2585.
`;cmd` – use "($cmd) && true" instead of detach [#4659].

If this works without problems on Linux, we're good to go.
missing imports in quaternion example
fixed println in quaternion example
added missing quaternion constructor and promotion rule
NEWS: various copy and punctuation improvements.