Change Ability from interface to abstract class
Change SpeciesRepository from interface to abstract class

This was to allow subclassing, and support caching.
Fix formatting of documentation and code.
Add .gitignore and Ant build.xml
Format Species
Add functionality to Pokemon

1. Reformatted the Pokemon documentation
2. Added hitpoints field
3. Added adjustHitpoints() method for when Pokemon is being healed for
   more than their maxiumum hitpoints.
4. Added slight level-up functionality (very basic).
Format Actor
Format PokemonContainer

I'm still not convinced that this is the way that I want to handle the
Party and storage box functionality.