Class metadata for PIR/assembly files

[Melvin Smith]

Regrettably, this won't be committed for 0.0.12 release since it is
definitely new
feature. If I commit now Leo would probably pummel me with flaming pumpkins,
so I'm going to play nice and follow the rules.

This is what I have currently in my working copy of imcc. I think this does
what we want for getting started.

.class MyClass
.field int i
.field int j
.field string s
.method foo
.endclass

.sub _main
print "main\n"
end
.end

.method MyClass::foo
print "MyClass::foo\n"
.end

Dan, I know your example used .member, but I feel like there is
value in separating them into .field and .method. For one, some
high level languages might allow data members and methods with
the same name.

-Melvin