Add continuous sending and synchrone dimming

[sgoudsme]

I moved the send command from the DMXGateway class to a separate thread. Also by changing the "yield from" to "asyncio.ensure_future" it will run parallel and allows changing multiple channels at the same time.
I think it is an answer to issue #5 and issue #6 .
I don't know if it is a good idea to start separate threads in home assistant, but it is running just fine on my raspberry pi.

[jnimmo]

Thanks very much for that I've incorporated the async fix, and will have a look at the threading soon - it is a hard requirement for my use that it doesn't continuously send packets, so just want to add an option to what you've done to allow disabling that

[maxenced]

Any news on this one ? I'm especially interested by the continuous sending, which is required to keep some kind of EFX live in software like QLC+