None linear random controls

[Eloi Andaluz]

Lots of options in Tyflow has a random option. But its always linear, and with big quantities of particles, linear looks always not very "natural" .
Will be cool to have next to each "Random" a button, where we can switch, between:

-Linear
-Exponential
-Exponential2
-Exponential3
-Custom curve
-map?

[tyFlow]

It's a good idea and for a long time I've meant to address that issue, because yea there are plenty of times when more variation options would be nice. Perhaps a little menu like that is the trick. I'll have to think more about it...