Api additions


Repost of what is included:
    restricting ApiEntity to take classes that extend Entity
    added a way to change the client brand
    ApiWindow can be used to change the window title/icon
    ClassPath can be used to load files from the assets folder
    Added support for a custom Container, this one I haven't been able to test though
    Improved BLLogger
    Added APIWorld.getEntitiesNear and getEntitiesOfTypeNear
    Made FieldInstance is type parametrized(funny spelling) and includes a get and set