Clarifying the terms "inputs" and "outputs"

The spec uses the terms "inputs" and "outputs" in various places. These
terms are ambiguous and in fact are used to mean different things in
different places:
* Sometimes a node N's "inputs" and "outputs" mean "ports" to which other
nodes could be connected. This is the normal meaning. For example a
GainNode's numberOfInputs is 1 no matter how many nodes are connected to it.
* Sometimes a node N's "inputs" and "outputs" mean nodes connected to N.
For example, in section 4.13 the phrase " "the synthesized data if there
are no inputs" refers to nodes, not input ports.

Both of these interpretations are quite natural and people have gotten
confused about this. I think it would help to use the term "input ports"
for the former and "input nodes" for the latter and to be careful never to
use the ambiguous term "inputs" alone. If people are happy with the "input
port" terminology then we might also want to change the
numberOfInputs/Outputs attribute names to numberOfInput/OutputPorts. (As I
understand it, these are seldom used currently so we probably can change
their names.)

Rob
-- 
Jesus called them together and said, “You know that the rulers of the
Gentiles lord it over them, and their high officials exercise authority
over them. Not so with you. Instead, whoever wants to become great among
you must be your servant, and whoever wants to be first must be your
slave — just
as the Son of Man did not come to be served, but to serve, and to give his
life as a ransom for many.” [Matthew 20:25-28]