TODO

These are more like ideas than like unimplemented features.  I.e. they
are not obviously good or have both benifits and drawbacks.



			    NAMED SIGNALS

It would look like this: there is a single object (maybe
`SignalFactory' or `SignalCollection', don't know yet.)  Its
__getitem__() operator is overriden to get single string---name of
signal---and return `AbstractSignal' subclass instance, an internal
proxy consisting of reference to the factory and the name.

Factory would maintain a single list of handlers, indexed by signal
names somehow.  This makes them useful: a single factory would take
less memory than several `Signal's.

Note that factory would _not_ implement `AbstractSignal' itself, only
returned proxies would.

It is unclear if a factory should impose any restrictions on signal
names.  Probably yes, at least optionally.

Sample usage would look like this:

       factory['create'].connect (...)
       factory['create'] (some, list, of, arguments)

Optimized usage (that avoids creating proxies all the time):

       signal = factory['create']
       signal.connect (...)
       signal (some, list, of, arguments)

In both cases, `create' is a name of the signal and has absolutely no
special meaning to `factory'.

As an alternative to __getitem__(), factories may provide a custom
__getattribute__() instead, with the same meaning.  I.e. instead of
`factory['create']' you'd write `factory.create'.  On the upside we
have a nicer syntax, on the downside we lose possibility to add any
methods.