NG: Configuration parser

Implements the configuration spec as defined in #646 with initial configuration version 0.1.
@dmp42 @wking @visualphoenix 
Should there be a `ParseVersion` function? Will the YAML library automatically extract this type?

It might be better to declare `type Version string`, then have methods `Major` and `Minor` that actually parse the contents. If the answer to the second question above is no, this will keep the field valid without an extra parse step.