merge default into stable for 2.3 code freeze

merge with crew

merge with stable

windows: removed duplicate termwidth definition Changeset dbf91976f900 caused this when the "from win32 import *" line was replaced with explicit import statements: the wildcard import was at the bottom of the file and so windows.termwidth was overwritten by win32.termwidth as indented, but the new explicit import statements were at the top and so win32.termwidth got lost. With the switch to ctypes, win32 can always be imported and so the fallback termwidth in windows is no longer needed.

httprepo: ensure Content-Type header exists when pushing data Otherwise the wireprotocol just hangs while trying to send data. (And nothing is received at the other side)

obsolete: obsstore.add now takes a list of markers. This allow efficient IO and it greatly simplify the merging of markers.

obsolete: refactor writemarkers to only encode them The function is now able to write the version header as necessary. The function now yield bytes to be written to a stream. This should ease later use of this function for wireprotocol based exchanged. Prepare the public use of the writemarker by wireprotocol function.

update: put rules for uncommitted changes into verbose help section

hooks: print out more information when loading a python hook fails When loading a python hook with file syntax fails, there is no information that this happened while loading a hook. When the python file does not exist even the file name is not printed. (Only that a file is missing.) This patch adds this information and a test for loading a non existing file and a directory not being a python module.

perf: fix perfcca to work with new casecollisionauditor interface A recent changeset, afd75476939e, modified the caescollisionauditor interface but did not update perf.py. This changeset remidies that.