relax AbstractBinaryStoreTest to support any BinaryStore implementation, not just AbstractBinaryStore
move start/shutdown methods from AbstractBinaryStore up to the BinaryStore interface
relax JcrRepository's binaryStore to support any BinaryStore impl
Create a StrategyBinaryStore that:

- initializes any number of child BinaryStore instances
- looks through all BinaryStore instances to find a BinaryKey
- appear as a vanilla BinaryStore to existing code
- persist content into a child store based on a "strategy hint"
add createBinary(InputStream, StrategyHint) method, and pass hints all the way through to BinaryStores.