This reverts commit d09b421d.

Try to put out darwin tinderbox fire

rt: Split out shapes into rust_shape.cpp and rust_shape.h so that shape code can be written outside of rust_shape.cpp

Ridiculous stuff like (ret 0) == (log "error")

Some of these don't actually work.

Uncomment parts of the test that work correctly now, enable pretty testing

(Since the variable won't be used after return anyway.)

This reverts commit 1ec2211a.

As it turns out, it's not just unops we need to worry about. Also tuples and
anything that requires parens.