subrepo: add "_cachestorehashvfs" to handle cache store hash files via vfs
This "vfs" object will be used by subsequent patches to handle cache
store hash files without direct file APIs.
This patch decorates "_cachestorehashvfs" with "@propertycache" to
delay vfs creation, because it is used only for cooperation with other
repositories.
In this patch, "/" is used as the path separator, even though
"self._repo.join" uses platform specific path separator (e.g. "\\" on
Windows). But it is reasonable enough, because "store" and other
management file handling already include such implementation, and they
work well.
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install:
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
Running without installing:
$ make local # build for inplace usage
$ ./hg --version # should show the latest version
See http://mercurial.selenic.com/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.