md2d scripting api: set properties on arrays of elements
create Mixing Liquids interactive

[#54874264]
particle mixing: tweak model size to stop model diverting

[#54874264]
Fix radioController to be selected if it's model is active

Previously radioController options with "loadModel" set, i.e
those that switch between models, like
http://lab.dev.concord.org/interactives.html#interactives/sam/light-matter/sun-on-ground.json,
would not be selected when a new model was loaded.

If no property is set, nor any loadModel, we want to just do nothing when
a model reload events happens.

[#57182806]
Move Run Benchmarks button to top right

We want to make it as easy as possible to run benchmarks
without scrolling
Automatically open benchmarks tab when benchmarks are run

Benchmarks can now be started with tab closed: we should
open it immediately so user can see results.
Disable zero button after data collection

IS [#57147438]
Really, only allow zeroing force and motion

IS [#57179962]
sensor model: freeze sensorType after collection 

IS [#57147498]
sensor model: don't allow clicking disabled zero
viewState: append overlay only once!
Cancelable model reset

IS [#57179922]
export controller: allow reset to be canceled

IS [#57179922]
ITSI copies of Energy2D convection models
refactor initialization

this decreases the chance of deadlocks on startup
it should also decrease the startup time.
[#56592122]
[#56615394]
applet calls javascript when it is ready

This fixes an issue with FireFox on OS X and some versions of
Java 7. It is also a more efficient way checking if the applet
is ready. And finally it might also reduce the blocking of the
JS thread because it won't be trying to call into Java so much.

[#56872730]
use the signed jar instead bare class

this removes the warning about running unsigned code

[#56994066]
Don't reference applet too early

see: http://concord-consortium.github.io/applet-tests/timing/
also this changes to the call to remove to dig into an
issue with IE reloading the applet when it is removed

[#56872730][#56994202]
use IE safe applet removal approach

http://concord-consortium.github.io/applet-tests/removal-of-tag/
[#56994202]
fix formatting