* Add initializeGL and deinitializeGL methods to OpenSpaceModule Call releaseAll from ProgramObjectManager in deinitializeGL to guard against errors when deinitializing assets
* Change removeProgramObject function in RenderEngine to take a non-owning pointer instead of a reference to a unique pointer to make it compatible with the ProgramObjectManager
Update Ghoul repository
* Using ProgramObjectManager in more modules to reduce the number of programs compiled at startup
* Adding ScreenSpaceSpout object to display spout textures in screen space
* Enable the clearing of option properties
* Fix crash in ScreenSpaceImageLocal specification
* Split RenderablePlane into RenderablePlaneImageLocal and RenderablePlaneImageOnline
* Add RenderablePlane Spout
* Rename Texture parameter in ScreenSpaceImageOnline into URL
Closes#518
Shadow cylinders extending from planet terminator in opposite dir of sun
Plane that displays the global texture map of a planet as projections appear
^latter is an addition to RenderablePlane class, a renderable plane can have
boolean keyword "ProjectionListener" - determines whether or not it displays