Feature/dashboard (#431)

Merging Dashboard branch that introduces the Dashboard, DashboardItem and moves most of the screen rendering code into a component-based layout that can also be displayed as a screenspace renderable

* Add Onscreen Dashboard
  * Add Dashboard class
  * Add DashboardItem classes and subclasses
  * Added font and fontsize customization to dashboarditems
  * Add default dashboard specifications to all scenes
  * Add tests.scene to test dashboard items
  * Add configuration options to DashboardItemDistance
  * Fix distance conversion to correctly use singular or plural values
  * Make DashboardItems unique when adding them to a dashboard
  * Correctly position test with different font sizes
  * Add Dashboard Item that enables spacing between other items
  * Add performance measurement to dashboard rendering
  * Add method to DashboardItemDistance that computes distance to surface
  * Add DashboardItemAngle that computes and prints the angle between three objects
  * Add DashboardItemInstruments that shows the instruments on New Horizons
  * Add ability to OpenSpaceModules to return a list of Luascripts defined by child objects
  * Make it possible for ScreenSpaceDashboard to work with its own dashboard or the main one

scripts/scene_helper.lua

@@ -12,6 +12,14 @@ openspace.documentation = {
         Documentation = "This function sets the default GUI sorting for the space " ..
         "environment to increasing size, from solar system, through Milky Way, " ..
         "Universe and finishing with other elements"
+    },
+    {
+        Name = "set_default_dashboard",
+        Arguments = "",
+        Documentation = "This function sets the default values for the dashboard " ..
+        "consisting of 'DashboardItemDate', 'DashboardItemSimulationIncrement', " ..
+        "'DashboardItemDistance', 'DashboardItemFramerate', and " ..
+        "'DashboardItemParallelConnection'."
     }
 }
 
@@ -23,6 +31,28 @@ openspace.mark_interesting_nodes = function(nodes)
     end
 end
 
+openspace.set_default_dashboard = function()
+    openspace.dashboard.addDashboardItem({
+        Type = "DashboardItemDate"
+    })
+
+    openspace.dashboard.addDashboardItem({
+        Type = "DashboardItemSimulationIncrement"
+    })
+
+    openspace.dashboard.addDashboardItem({
+        Type = "DashboardItemDistance"
+    })
+
+    openspace.dashboard.addDashboardItem({
+        Type = "DashboardItemFramerate"
+    })
+
+    openspace.dashboard.addDashboardItem({
+        Type = "DashboardItemParallelConnection"
+    })
+end
+
 openspace.set_default_gui_sorting = function()
     openspace.setPropertyValueSingle(
         'Global Properties.ImGUI.Main.Properties.Ordering',
@@ -30,4 +60,4 @@ openspace.set_default_gui_sorting = function()
             "Solar System", "Milky Way", "Universe", "Other"
         }
     )
-end
+end