Removes some invalid safety annotations and adds a workaround for a starvation issue in Task.join() across threads boundaries. This is still not thread-safe, but now has a safety-net and is documented, so that it doesn't get lost.
The library is able to support simple TCP servers in the current state. The API is still mostly compatible with mainline vibe.d, but the driver systen has been replaced by the eventcore library and sockets/files/timers/... are now structs with automatic reference counting instead of GC collected classes. The stream interfaces have been removed for now.
