Merge pull request #16 from caridy/master

defaultBundle is not longer required, but optional
adding docs for optional defaultBundle
adding buildCSSUrls and buildJSUrls as low-level apis to build url and combo urls based on modules names. refactor getSeedUrls() to use those methods under the hood.
adding unit test for PR #11
review feedback
adding history entry
fixing typos
Merge pull request #17 from caridy/css-modules

adding buildCSSUrls and buildJSUrls as low-level apis to build url and combo urls based on modules
bumping version 0.5.5
updating docs for 0.5.5