v0.13.0

A dash is the stream

Every option that names a file takes - for the stream instead.
--emit-elf, --emit-wasm and --emit-object write to standard output;
--run-wasm reads from standard input. So the two wasm tiers compose with
no file between them:

python3 ouroboros.py --emit-wasm - | python3 ouroboros.py --run-wasm -

The artifacts are binary, so they go through the buffer under sys.stdout,
and the rendering steps aside when one of them is bound for the same place:
it is the default output, and an artifact asked for by name outranks it.
What goes down the pipe is the whole artifact and nothing else - 1274 octets
for the executable, the same as the file.

--workdir names a directory rather than a file, so it keeps a real path,
and its metavariable now says DIR to stay outside the rule. The one thing
standard output cannot carry is the executable bit, which it does not need:
whoever redirects it decides what it becomes.

Full Changelog: v0.12.0...v0.13.0

LOC: 12716