Restart the simulation without 100% heat.

[mbostock]

Currently, simulation.restart sets iteration to zero, thereby setting alpha to one. There’s no way to set the maximum alpha or restart to a slightly later iteration, but I think we’ll need something like this for interactive dragging (#22).

[mbostock]

Related to this, one problem with simulation.alphaDecay(0) is that it always sets the alpha to 1. This sort of makes sense, but what if you want to set the alpha to another value less than one, but not have it decay further? That’d be nice, because then you could avoid having to call simulation.restart after every tick.

[mootari]

Was the removal of the return value in .tick() intentional or by accident? (Return was introduced in #20).