Modified Buffered1Chan<T> to be a direct descendent of Chan<T>, and simplified the write() and read() methods.

[ Benchmarking notes with 2800MHz Xeon 5400 ]
By avoiding the repeated use of overloaded methods, a message-passing event is now about 4 microseconds faster than before.
Contention and thread swapping is still by far the costliest item, but the contrived no-contention message passing tests went from 5.0 to 1.1 microsecond per message.
This 1.1 microsecond per message is in comparison to just over 130 nanoseconds per message in the equivalent test in Go.