Adds sane defaults

The idea is that you can simply provide a string (i.e. the dirname of the folder to require) and some sane defaults are assumed:

* require all json files
* require all js files
* exclude anything in .svn or .git

I did some styling changes (75a2d31) to make this more consistent with the overall style of code. However, feel free to cherry pick around those changes.

A bug fix related to bad semver handling was also fixed in a45342f.

Documentation and tests included in the patch