Images for home screen and navigation bar

[jessegreenberg]

I had forgotten that we have template images for these currently, especially for Measure and Graph screens. @arouinfar can you please create new images for this?

[jessegreenberg]

Here is what we have now

[arouinfar]

Some rough ideas for discussion in design meeting

Intro: Skater on double well track with energy pie chart on

Measure: Skater on parabola track, path dots on, probe on dot. Data would be hidden, and the probe could be cartoonishly big.

Graphs: Maybe superimpose E(x) graph over the track. Details would be simplified.

Playground: Something fun, maybe the dog in the loop. (Control points are missing because this was a quick screenshot from Intro.)

[arouinfar]

Feedback in 4/23/20 design meeting

• Try showing just the graph for the Graphs icon
• Might want to zoom in more on Playground icon

[arouinfar]

Based on our discussion during design meeting, I've cleaned up the icons. @ariel-phet can you take a look and let me know your thoughts?

Screen	Icon
Intro
Measure
Graphs
Playground

[ariel-phet]

@arouinfar those all look the correct direction to me. My only concern is on the navbar, so you might want to see how they look at that size, but looking at ESPB, it seems like these all should work.

[arouinfar]

Thanks for your feedback @ariel-phet! I had similar concerns about navbar readability, but these seem on par with the ESPB icons.

I cleaned up the icons a bit, and updated the color of the ProbeNode based on the decision made in #176. @jessegreenberg here are the assets for the screen icons:
screen-icons.zip

[jessegreenberg]

New screen icons have been added @arouinfar, can you review their look in the sim?

[arouinfar]

Looks great, thanks @jessegreenberg!