named arguments - internals

As mentioned earlier today, I've rewritten the guts of the argument
passing code. It's now one function 'process_args', which is mostly a
state machine with currently ~12 cases that handles the various states
or should eventually handle.

Anyway, previous functionality and named arguments passing is working
with it already, so far as tested before. Missing is still handling of
optional named params, as well as all the error checking with named
arguments/params. But with the new state machine all these checks are
just filling a case statement which is partly done with a TODO comment
already.

The code passes all core and languages tests except the already
mentioned:

lua/t/function.t 1 256 2 1 50.00%

therefore I've just checked it in as r11276.

A lot more tests are needed for all the variations of arg passing.
Contributions welcome. See t/op/calling.t (labeled 'named \d' for
existing PASM tests) or t/op/cc_params.t (for a more automated test
generation - thanks particle).

And Alberto (ambs) has started to hack imcc.y for the
necessary/proposed PIR support.

leo