py3: add pycompat.open and replace open() calls open() requires mode argument as unicodes on Python 3. This patch introduces pycompat.open() which is inserted to files using transformer and replaces builtins.open() calls.

localrepo: deprecate 'repo.opener' (API) The "new" 'repo.vfs' attribute have been around for almost 5 years. I think we can deprecate the old form now ;-)

statichttp: use 'repo.vfs' as the main attribute We are about to deprecate the repo.opener attribute, we prepare the static http code to be ready for this change.

clonebundle: use 'repo.vfs' instead of 'repo.opener' The later is a 5 years old form.

localrepo: deprecated 'repo.wopener' (API) The "new" 'repo.wvfs' attribute have been around for almost 5 years. I think we can deprecate the old form now ;-)

localrepo: add some comment about role of various vfs object This should make things clearer for most people.

tests: un-nest the `order` repo in test-rebase-scenario-global This wasn't hurting anything, but it's more in line with how we manage other tests.

osx: install bash and zsh completions by default The zsh location appears to be on the default $fpath for zsh. bash, on the other hand, appears to have no default location for completion scripts, so we follow the lead of Apple's Git distribution and select a semi-arbitrary place in /usr/local for the file.

util: add allowhardlinks module variable To enable extensions to enable hardlinks for certain environments, let's move the 'if False' to be an 'if allowhardlinks' and let extensions modify the allowhardlinks variable. Tests on linux ext4 pass with it set to True and to False.

merge with stable