$ cargo clean
$ cargo build
Updating git repository `https://github.com/softdevteam/cfgrammar`
Updating git repository `http://github.com/softdevteam/lrtable`
Updating registry `https://github.com/rust-lang/crates.io-index`
error: failed to select a version for `regex` (required by `cfgrammar`):
all possible versions conflict with previously selected versions of `regex`
version 0.2.1 in use by regex v0.2.1
possible versions to select: 0.2.2