Add Time.timeScale

[RhenaudTheLukark]

If I remember correctly, the main problem with this feature is that it doesn't apply to the engine entirely; frame counters can't be affected by this feature, and it seems it's also pretty easy to reproduce on the Lua side, nor does it potentially run the Update() function several times if time is sped up, or skips frames if time is slowed down.

I personally don't think this feature is needed really, unless you can convince me otherwise.

[deonix37]

1. No engine implements frame scaling, but most engines implement time scaling
2. Without time scaling we can't dynamically scale the timing of UI animations and dialogue
3. Instead of reproducing this in Lua by multiplying everything by our own variable, it's much better to multiply everything by Time.mult (which is, again, a common practice in every other game engine) and easily control the global time scale by utilizing Time.timeScale
4. Time.mult would become twice more useful