add element_type parameter to atomsWithin
performance tweaks and alternate stopping condition for diffusion temp
reverting change to atom distribution in diffusion mml
gas sensor image in diffusion models
cleaning up unnecessary versions
Merge pull request #21 from concord-consortium/wip_diffusion_cleanup

Wip diffusion cleanup
Support clicking an atom in "Basic Diffusion on click" Interactive

[#44616231]
Implement getFPS() and getSimulationProgressRate() in MD2D modeler

[#46121501]

getFPS() just returns frames per second.

getSimulationProgressRate()returns a value which presents how many
femtoseconds of simulation are calculated during one "real" second.
So, it shows real speed of the model progress.
Make getFPS() and getSimulationProgressRate() available in ScriptingAPI

[#46121501]
Show FPS and Simulation Progress Rate in one interactive

[#46121501]

... in: "Oil and Water for Slow Computers"
Reset lastSampleTime when simulation is resumed

[#46121501]
increased minimum volume and reduced pressure measurement range

[#46392685]
Improve interactive for performance tuning on slow devices

[#46121501]
Provide performance utils with window.performance.now when available

[#46121501]
Implement automatic MD2D performance optimizer

[#46121501]

It tries to ensure that the simulation speed is appropriate and
animation as smooth as possible.
Use automatic performance optimizer in "Performance Tuning" interactive

[#46121501]
Refactor bar graph view to scale linearly with font size

[#46685027]
Report the full 20/sec for force and motion
Fix zero-ing sensors that support it
Use the same rounding code as the rest of the IS code