rustpkg can now build code from a local git repository. In the
case where the local repo is in a directory not in the RUST_PATH,
it checks out the repository into a directory in the first workspace
in the RUST_PATH.
The tests no longer try to connect to github.com, which should
solve some of the sporadic failures we've been seeing.
The removed test for issue #2611 is well covered by the `std::iterator`
module itself.
This adds the `count` method to `IteratorUtil` to replace `EqIter`.
Automate more tests described in the commands.txt file,
and add infrastructure for running them. Right now, tests shell
out to call rustpkg. This is not ideal.
