Each bytecode now carries exactly one argument, but the arg is only an
extra layer of tuple if the handler method needs more than one
parameter.

The handlers are also modified so that they require exactly one
argument, which is a tuple only if they need more than one argument
from the instruction.  This simplifies the dispatch code in
TALInterpreter.interpret() just slightly.

Changed the version number of the bytecode again, since Guido tells me
Evan calls this version 1.3.2.