windows: seek to the end of posixfile when opening in append mode The position is implementation defined when opening in append mode, and it seems like Linux sets it to EOF while Windows keeps it at zero. This has caused problems in the past when a file is opened and tell() is immediately called, such as 48c232873a54 and 6bf93440a717. Since the only caller of osutil.posixfile is this windows module, this seems like a better place to fix the issue than in osutil.c and pure.osutil.

context: use unfiltered repo for '.' There is no reason to read obsolescence markers when doing a plain 'hg status' without --rev. Use the unfiltered repo when initializing context._rev to speed things up. This speeds up 'hg status' from 1.342s to 0.080s on my repo with ~110k markers.

check-commit: check capitalization in summary lines At the moment, check-commit will complain about the topic being capitalized, but not the summary that comes after it. This diff corrects that deficiency.

bundle2: seek in part iterator When iterating over bundle2 parts, add a seek to the iterator so that processing will continue normally even if the entire part isn't consumed.