Add missing return value deconting.

Or at least, the common case. Fixes explosion in Rakudo spectests.
Update status, add a feature overview.
First pass at a CREDITS file.
Accept NEL into newline cclass.
Eliminate an incorrect fixup to line numbers.
Fix bytecode annotations dumping.
Account for PC pre-increment; diakopter++.
Ensure we don't -1 a 0 offset; diakopter++.
Fix off-by-one in annotation lookup.
Missing sanity check in autoclose.
Align arity-related error generation with Rakudo.
Align missing named param error with Rakudo's.
[Build] "release" Makefile target
back out these changes temporarily or not
Add assertparamcheck, to help with arg type checks

This will be used to add a new feature to the Moar code-gen in NQP,
which in turn will be used for binder fast-pathing in Rakudo.
Decont while auto-unboxing.

Works for the common case.
Remove leftover debugging code
try to add aliases and gc value aliases # who knows whether it will work
try again
pass a couple more tests... need more though.