context: add 'dirs()' to changectx/workingctx for directory patterns
this patch adds 'dirs()' to changectx/workingctx, which returns map of
all directories deduced from manifest, to examine whether specified
pattern is related to the context as directory or not quickly.
'workingctx.dirs()' uses 'dirstate.dirs()' rather than building
another copy of it.
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
See http://mercurial.selenic.com/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.