size_t

Another batch of size_t fixes, i.e. replacing int counters over the particles by size_t to allow for more than 2G particles per rank.

There's no hurry for this, mainly cosmetics and future-proofing.

Added 96 commits:

• 045461a6...4effc52c - 94 commits from branch master
• 7f14ce33 - Merge branch 'master' into size_t
• c4dffca7 - Fix merge issue

This branch no longer merged cleanly, so I've updated it. Can you check that this looks correct.

That looks good to me. One part of the lengthy process of breaking the int barrier everywhere.

Status changed to merged

mentioned in commit 93ce6618

OK, accepting. Pedro make sure you pull this branch before adding more fixes.