Ensure that the command line always exits with the correct error code.

In the previous implementation if stdout and stderr drain before the
callback is created it will exit with a 0 status even on a failure.
fixes clutchski/coffeelint#88
Replaced the pretest command with 'rake compile'

Prepublish doesn't trigger on Node 0.6 which leaves the build broken.
Only the command line tests were failing because bin/coffeelint wasn't
being created.