Fix cmd parsing & update tests

Implement parsing for rnd and add a little documentation

Undo enabling the `unreachable-pub` lint. It appears that nom cannot correctly handle `pub(crate)`, so the warnings cannot be fixed at the moment. See https://github.com/Geal/nom/issues/807

stabilization

Fix spectators joining midgame

Send more data on room joining

Additional round cleanup

neglected dep update from r87a6cad20c90: that rev also forces nightly rust due to https://github.com/rust-lang/rust/issues/23121

Send teams&flags on entering a room

Implement game start & engine messages

Implement game config messages

Enable all lints from the rust-2018-idioms suite. Additionally, fix the violation of the bare-trait-objects lint.