kspace pppm/tip4p with a triclinic unit

I have tested pair_style lj/cut/tip4p/long with my modified pppm/tip4p
that supports triclinic and all seems to be working. This should
(hopefully) be released sometime next week.

Stan

FYI, this tip4p bug is now fixed and pppm/tip4p now supports
triclinic, so you should be good to go.

Stan