Remove spaces that somehow sneaked in.

timotimo++ for reporting.
Serialization of cloned code refs.

Doesn't yet serialize the context, but this is the first half of the
closure serialization and passes a bunch of the 03-closure.t tests.
Finish up closure serialization.
Add now-passing t/serialization/03-closures.t.
Remove bogus type conversion instructions.

Fixes /a**4/ bug, found by timotimo++.
Remove serialization from todo list.
Space-o fix; timotimo++.
Get BUILD fix.
A little re-org.
Don't leak compunits out, in general.

Just give them to things that know what to do with them.
Fix handle uniqueness issue.
We now pass 49-regex-interpolation.t in selftest.
Avoid null exception messages.
Implement nqp::rethrow.
Current handler shouldn't catch its own exceptions
Implement nqp::resume(...).
Remove a couple of completed items.
Update for latest serialization changes.
Fix serialization tests.
Add partial P6bigint REPR and some basic ops.

This is enough to pass the first 5 of 60-bigint.t. Note that P6bigint
currently is not able to embed itself into a P6opaque.