- update the common problems page with the section about data not loading because of python...changed the solution instructions now that we bundle python with cave
- update the d2d-perspective page so it has a subsection on how to remove an individual resource using the resource menu
- add an image for single resource unloading
- removed several unused .md files
- removed instances of "Unidata" (replaced with "NSF Unidata" or something else)
- add note to d2d-perspectives about GFE only supported with OAX site
- removed all images that don't apply for v20
- removed several extra files that aren't necessary (in the docs/pdf/ and docs/python/ directories)
- renamed some images that were preserved that had random character names, to something descriptive
