Add support for projects using the pre-commit tool

• make lb-project-init invoke pre-commit install if the special file .pre-commit-config.yaml is present in the project
• make lb-dev projects inherit (copy) the .pre-commit-config.yaml file from the main project and invoke pre-commit install

I also fixed a minor issue in lb-project-init generation of local .gitignore.

Closes #67 (closed)