Loosen the definition of "lossless" a bit so that we can use high
quality JPEG to refresh damaged parts of the screen. Although this
isn't bit perfect, it is close enough that most users will not be
able to tell the difference.
Level 9 is used rather than level 8 because some monitors have
exaggerated contrast that allows the artefacts from level 8 to be
noticeable.
Resend pixel perfect copies of areas that were previously sent
using a lossy encoder. This is done when there is no normal update
to send, and no congestion.
Move image encoding logic into a central EncodeManager class
This allows us to apply a lot more server logic
independently of which encoder is in use.
Most of this class are things moved over from the
Tight encoder.
Pierre Ossman