Pr/scenegraph refactor

Update WMS specification of GIBS datasets

- Remove syncables before deinitializing openspaceengine

Disable GDAL test until new Windows GDAL binary is included

Update Ghoul repository

Update Ghoul repository

Allow an Image SequenceParser to not return target times (used for the HongKang parser not returning any if Lorri is ignored

Make registerting path tokens through Lua scripts work

Cleanup of RenderableFOV
Add function to SpiceManager that does not return the light travel time

Make OpenSpaceTest not flood the console on Jenkins
Fix Vec3 property to signal change correctly
Let RenderablePlanetProject correctly reload base map and height map
Update Ghoul

Updating SGCT repository
Removing compiler warnings

Conflicts:
	include/openspace/engine/openspaceengine.h
	src/engine/openspaceengine.cpp
	src/engine/settingsengine.cpp
	src/engine/syncengine.cpp
	src/interaction/interactionhandler.cpp
	src/rendering/renderengine.cpp
	src/scene/scene.cpp
	src/scene/scenegraph.cpp
	src/scene/scenegraphnode.cpp
	tests/test_scenegraphloader.inl

Rename None to Hidden, to avoid collision with X11 and reset data path