Cruft

- [Improved 57](https://github.com/cruft/cruft/issues/57): Improve how a project can be updated to use new values of template variables

- [Implemented 57](https://github.com/cruft/cruft/issues/57): Accept cookiecutter arguments on the command line for update

- [Implemented 172](https://github.com/cruft/cruft/issues/172): Add support for local extensions

- Uncapped version requirements (including Python) for greater compatiblity
- [Fixed issue 166](https://github.com/cruft/cruft/issues/166): Fixed compatiblity with latest version of cookiecutter
- [Implemented 184](https://github.com/cruft/cruft/issues/184): Store checkout parameter when using link command
- Improvements to update command

- [Fixed issue 177](https://github.com/cruft/cruft/issues/177): cruft update can't apply diffs when git's diff.mnemonicprefix config is set