Set the Travis node environment to production.
Test the local version of the impromptu server.
Because you need Grunt installed if you want to run it.
Allow tests to be run without a global install.
Do not run grunt on npm prepublish.

This was fighting npm's implementation of prepublish, which also (strangely) runs on local preinstalls. We should only use prepublish for preparing or cleaning up state, not validating the package. It would be nice if there was a way to validate the package. I would like that.
Require npm 0.10.
Ignore tmp directory and impromptu logs.