Add verification cases for level set and boundary fuel and terrain_image

[rmcdermo]

Looking at the fds/Verification/WUI/ directory I would expect to see cases for each of the key flame spread mechanisms, physic-based, boundary fuel, LS1-4. Can we set up a nominally equivalent simple case and add to the verification guide. These would be similar to CSIRO, but even simpler. I use these verification cases as my go-to for my initial setup.

We also need a large case that uses a generic terrain image so that we are assured these get set up properly. The Smokeview image can be rendered and stored for image comparison. Again, this provides a quick example for anyone trying to set up a new terrain case and we are assured it works with latest inputs and Smokeview.

[mcgratta]

I used qgis2fds to create an FDS input file for a roughly 2 km by 2 km patch of mountainous terrain. I ran a fire simulation for 10 h real time using level set 1 through 4. I will add the input files to the WUI Verification folder, but because the case uses 182 meshes, a 2 MB geom file, and 8 h for the LS=4 case, I will not have these cases run each night. Instead, I'll add the figures to the fig directory.