* LIFX: improve performance of multi-light transitions
To avoid hub overload, the light.turn_on call will change each light
sequentially.
As LIFX has no hub we can safely increase performance by starting all
light transitions concurrently.
* Improve state updates after light changes
The light.turn_on call will set a new state and then immediately read it
back. However, reading the state of a LIFX light right after a state
change can still return the old value.
To handle this situation we have previously delayed the update request a
little while to allow a potential state change to settle. Because light
updates are now run in parallel, this delay might be too short when many
lights are set at once.
This commit introduces a per-light Lock to make it explicit when the
state cannot yet be trusted.
We must then do the state update ourselves. This was already done at the
end of a long transition and that code can be reused for also doing the
update at the start of a transition.
Anders Melchiorsen
317bc10ccb