Priority handling for user-input in Chat and IM to improve performance

User-input should be independent of the sim load, frame draw rate or physics sim rate if it is handled by priority scheduling rather than time-slicing.

Accepting only 1 or 2 characters per sec when you type in Chat or IM is unacceptable. It can be improved significantly if user-input is handled on a priority basis, with the highest priority, while the animation can be set at a lower priority.

In other words, we don't really care if the animation is dropped down to 1 frame per sec, but we do care when input is slowed down to 1 character per sec, it is very irritating, and wasting our time staring at the keyboard or the screen.

The event-handler should have a priority setting, handling user-input first, and animation last. This would improve the user-experience significantly.