Silently doesn't create entry output if no absolute paths are used

[Pita]

I think this is related to #29

I created again a demo repo: https://github.com/Pita/repro-factor-bug-3

1. npm install
2. node build.js
3. notice no error was thrown, but no out.a.js or out.b.js were created

[terinjokes]

I know this to be false. This is how I generate bundles. All your packages are considered part of the "common" bundle. Please use the files from the test/deps directory.

[terinjokes]

This might have been resolved with 2.2.4.