[$] 4.16 Merge window part 1

As of this writing, just over 6,700 non-merge changesets have been pulledinto the mainline repository for the 4.16 development cycle. Given thatthere are a number of significant trees yet to be pulled, the earlyindications are that 4.16 will be yet another busy development cycle. Whatfollows is a summary of the significant changes merged in the first half ofthis merge window.