Added some metadata to the root pom.
Attempt at automatic site generation - not working yet.
Added a new generic transform to the basic extensions.
This will enable users to change the predefined severities of compatibility
types on found differences. Useful for example to force @Deprecated elements
as breakages to force them to be explicitely ignored and thus reported on.
Moved the Difference class out of Report class to top level.
Configuration is now JSON-based instead of properties-based
so that lists and other more complex structures are easily
expressable.

Even with the 3 configuration extensions in the core codebase,
the properties started to annoy me :)