Fix setup process

This pull request contains two commits which fix two separate issues, both of which prevented me from running through the initial setup for this repo:

 - The version of mach specified in `package.json` couldn't be found, so I updated to the release canditate for 1.0 which seems to work without any problems
 - Supervisor was an undocumented global dependency, so I added it to  `devDependencies` and updated the `dev` script to point to this local version