maint: Redirect developers to active branch

_This_ branch does not contain actively-developed code.  More likely,
you want to check out branch-1.4 (latest stable), branch-1.6 (some
speedups over 1.4, but not yet released), or branch-2.0 (many more
experimental changes, and even further from release).

* README: Document the status of this git repository.
167 files changed
tree: 7c751929d43352234572cfe4d770c944b7c9b2c8
  1. modules/
  2. README
  3. README-alpha