…able

Using `EventHandler::setSequenceCallback` with the newly added concept of
Rewinding in the `BatchEventProcessor` is not going to go well as an
`EventHandler` can change the sequence before a rewind.

Non-rewindable `EventHandler` implementations are not able to throw a
`RewindableException`.

…y the rewind supporting build method

…ndler-separation2

# Conflicts:
#	src/main/java/com/lmax/disruptor/BatchEventProcessor.java
#	src/main/java/com/lmax/disruptor/EventHandler.java

# Manually fixed up:
#	src/main/java/com/lmax/disruptor/EventHandlerBase.java

An overly keen find & replace made more changes than necessary while changing from direct BatchEventProcessor construction to using the builder.