I have done a pass to make the APIs and internals more typesafe

Mainly starting using <?>. There is probably a lot of areas where it's missing.

It mean I did break some APIs (from an implementor PoV). If you have some generics in mind for the APIs, go for it now. Make sure to use <?> rather than the raw type (including for Class<?>).

We are down to 1 compilation warning.

Lucene has deprecated the InderWriter constructor we use in 2.4.