SPICE-time dependency, retrieval of spice ephemerides and rotational matrix + coordinate references.

Added functionality:
- New class renderablesphericalgrid is repurposed code from powerscaledsphere class.
  Due to z-buffer issues used as reference grid to confirm planetary orbits are correct.
  This has been a major problem as prior we had no visual reference.
  Now we have a Galactic-, Celestial- and Ecliptic-coordinate grid.
  To this also added separate shader: grid_vs.glsl / grid_fs.glsl
  These grids have a static-rotational matrix derived from partiview (thanks to Brian)
  since spice req. to-from frame to compute rotational matrix.

Time dependency:
- Added struct RuntimeData - which for now only contains openspace time and is passed to all renderables
- All renderables accept runtimeData, keep private reference and use for computation of rotational matrix
- This obviously carries corresponding changes to Scenegraph and ScenegraphNode.

Spicemanager:
- Added function that more easily provides access to rotational matrix used in spice
 (used in renderableplanet for computing planetary objects spin around axis)

Ephemeris-classes:
- Now compute ephemeris from spice based on timeepoch in runtimedata
  TODO: once z-buffer fixed - set ephemeris correctly as meters (not kilometers)

Renderengine:
- Advances time with the advanceTime method in RuntimeData struct

ISSUES:
- Our Y axis NOT same as SPICE or star-catalogue, all renderables rotated now 90deg, needs redefinition,
  lots of debugging and major headaches before this conclusion.
- Depth buffer needs to be fixed in order to properly place planets.
- Spice kernels have finite time-range, when time stops - simulation ends - ugly fix: reset time to zero.
  Possible fix: kernels de431 (part 1-2) cover huge timespan and most likely have functions to extrapolate time,
  drawback is that they are 1,7 gb each.

TODO:
- Compute and draw dynamic ephemeries for each renderable. Either do full year sweep then update for each point or
  create a tail of linesegments for each planet. Dont know yet how to do this, would like spicephemeris to be
  sub-class of Renderable (have own render() method) - good/bad?

src/scenegraph/scenegraphnode.cpp

@@ -117,6 +117,7 @@ SceneGraphNode::SceneGraphNode()
     , _renderable(nullptr)
     , _renderableVisible(false)
     , _boundingSphereVisible(false)
+	, _runtimeData(nullptr)
 {
 }
 
@@ -125,13 +126,15 @@ SceneGraphNode::~SceneGraphNode()
     deinitialize();
 }
 
-bool SceneGraphNode::initialize()
+bool SceneGraphNode::initialize(RuntimeData* runtimeData)
 {
     if (_renderable != nullptr)
         _renderable->initialize();
 
     if (_ephemeris != nullptr)
         _ephemeris->initialize();
+
+	_runtimeData = runtimeData;
     return true;
 }
 
@@ -162,7 +165,7 @@ bool SceneGraphNode::deinitialize()
 // essential
 void SceneGraphNode::update()
 {
-    _ephemeris->update();
+    _ephemeris->update(_runtimeData);
 }
 
 void SceneGraphNode::evaluate(const Camera* camera, const psc& parentPosition)
@@ -212,7 +215,7 @@ void SceneGraphNode::render(const Camera* camera, const psc& parentPosition)
 
     if (_renderableVisible) {
         // LDEBUG("Render");
-        _renderable->render(camera, thisPosition);
+		_renderable->render(camera, thisPosition, _runtimeData);
     }
 
     // evaluate all the children, tail-recursive function(?)