Depend on coffee-script 1.7.x

`updateSyntaxError` is not in coffee-script 1.6.x, so we need to make sure to specify the coffee-script version. Depending on `*` can cause a problem if: top level project uses the latest version of node-connect-coffee-script, but also depends on coffee-script 1.6.x. Because of npm's dependency resolution, if it sees `"coffee-script" : "*"` in node-connect-coffee-script's `package.json`, it will think this is already satisfied with coffee-script 1.6.x and won't install the latest version. So if there is ever a syntax error, it won't show up properly.

Also, in general I think it is a good idea to depend on a specific minor version of coffee-script because there might be breaking changes across versions that require updating the library.