Revert back to non-color compiler error message.

Add debug options for Elm 0.18

Fix bug from 0.4.3 where bundle task never ended

Fix error when bundling zero files

Update to cross-spawn from cross-spawn-async

Merge pull request #11 from abadi199/master

Use terminal's stderr when displaying compiler's error message.

Merge pull request #9 from abadi199/master

Replace child_process with cross-spawn-async for better support on windows