InductionRLCircuit apps

[lheagy]

Thanks @dccowan for your work on these! I have gone through the notebooks with @dougoldenburg and @sgkang and here is the synthesis of that conversation

Summary of Requested Changes

Two notebooks should suffice for explaining the 2 loop example:

• InductionRLcircuit_Harmonic.ipynb
• InductionRLcircuit_Transient.ipynb
  The additional plot that shows the response function (currently in InductionRLcircuit_FDEM_Harmonic) can be moved to InductionRLcircuit_Harmonic.ipynb.

Harmonic

• Most of the supporting mathematical theory should be moved to EM geosci and not included in the app. The final form of the solution can still be there
  
  the rest should be in EM geosci and a link provided for the derivation. To include a link:

<a href="http://em.geosci.xyz">text to link</a>

• a few requests on layout / visualization...

  • put a light grey line through 0 on both plots
    
  • please make the vertical extent of the above plots a bit smaller

• for layout, could you please

  • move the info currently listed in the top right panel (Bp, Bn, Area) to a semi-transparent box in the top left hand corner of the fields plot
  • the response function plot can be made square and replace the plot in the top right hand corner plot. The text info from this plot can be removed (it is either in the widgets or shown in the plots below).
    

Transient

• again, most of the Mathematical Theory can be moved to em geosci and linked. Just the main governing equation can be kept
  

[dccowan]

I've made the changes to these apps. The branch in em_examples is InductionLoopAppEdits. The branch in em_apps is PartitionInductionLoopApps. Doesn't seems like you are too hung up on sliders at the moment. If everything looks good, I can make the necessary pull requests.

[lheagy]

For widget type (eg. Float Text, or Sliders) - please give it some thought. I would be inclined to turn them all to Float Sliders (note that you can always enter the number in the box on the right). For Resistivity, I would slide over log_10(R) though to get the logarithmic variation.

cc @dccowan , @sgkang : what do you guys think?