* Rename OnScreenGui module to ImGui
* Support multiple external module folders (closes #31)
* Cleaning up CMake files
  * Restructure application specification
  * Add parameter for library mode to all modules
  * Add functions to handle global variable state
* Misc/remove warnings (#383)
* Increase build timeout and do a clean rebuild every commit

Misc/various fixes

Update Ghoul repository

Remove keybinding scripts
Remove satellites

Fix the spherical grid

Make GlobeBrowsing scene the new default scene

Unify the property names in RenderablePlanet
Remove MainFrame from RenderableShadowCylinder
Clean up dictionary keys for RenderableModel, RenderableModelProjection, RenderablePlanetProjection

Add Property descriptions to the documentation file
Remove update method from StaticTranslation
Remove spelling error in RenderableGlobe
Remove rotation from renderablemodel projection
Fix setting the Origin through the GUI
Reorder Optional and documentation arguments for DocumentationEntry, and making Optional a non-optional argument

Feature/property documentation

Adds documentation strings to properties
Fix all the errors that occurred during the change
Fix capitalization of property names

Restore backwards compatibility of mod files
Provide better feedback about specification errors

Fixing up YAML affiliations

Update SGCT repository
Update Ghoul repository

Add indexed affiliations
Add references to the Summary text