Removing the asset_helper file (#1868)

- Remove the asset_helper file and call the onInitialize and onDeinitialize functions directly
 - Small compile fix on Windows
 - Removes the need for the registerIdentifierWithMeta function by automatically doing that for all asset.export statements
 - Allow the passing of either identifiers (as before) or entire tables to the removeSceneGraphNode, removeScreenSpaceRenderable, deleteLayer, removeAction, and export methods. In that case, the Identifier key from the table is extracted and used instead

modules/globebrowsing/globebrowsingmodule.cpp

@@ -362,13 +362,13 @@ scripting::LuaLibrary GlobeBrowsingModule::luaLibrary() const {
         {
             "deleteLayer",
             &globebrowsing::luascriptfunctions::deleteLayer,
-            "string, string",
+            "string, string, (string, table)",
             "Removes a layer from the specified globe. The first argument specifies "
             "the name of the scene graph node of which to remove the layer. "
             "The renderable of the specified scene graph node needs to be a "
             "renderable globe. The second argument is the layer group which can be "
-            "any of " + listLayerGroups + ". The third argument is the dictionary"
-            "defining the layer."
+            "any of " + listLayerGroups + ". The third argument is either the identifier "
+            "for the layer or a dictionary with the 'Identifier' key that is used instead"
         },
         {
             "getLayers",