setup: add command to generate index of extensions
It generates prebuilt index of all extensions, which will be used by
frozen exe when running 'hg help extensions'.
Now py2exe invokes this command automatically.
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.