remove unused method with problematic semantics
naming convention on sys prop constant
using basis 2.2.0-SNAPSHOT

mostly for v8 hashmaps
channel state not extending simple handler

as in the netty4 branch
removing receiveComplete(int) from SessionHandler

though both are implemented by source/target handlers, each
implementation is private/final and not really appropriate
to call publicly
fix weird semaphore use in TargetHandler

another instance of acquiring a semaphore lease immediately instead
of initializing with 0 leases. Instead of changing lease count, just
using a CountDownLatch since that is the actual intention
use V8 conc hashmaps