merge with stable

commands: move bundle type validation earlier Checking the bundle type late in the command's execution can mean that we do work for a long time before complaining about incorrect user input and aborting. Guess how I discovered this.

changegroupsubset: optimize function lookup in prune

changegroup: optimize gennodelist

revlog: drop some unneeded rev.node calls in revdiff

revlog: avoid an expensive string copy This showed up in a statprof profile of "hg svn rebuildmeta", which is read-intensive on the changelog. This two-line patch improved the performance of that command by 10%.

changegroupsubset: avoid setdefault in inner loop

changegroupsubset: drop repeated len() calls

changegroup: reduce progress overhead

changegroupsubset: renest inner loop The mdata list should generally be shorter than changedfiles