Changing API Compatibility Level to .NET 4.6

Author: keveleigh

ProjectSettings/ProjectSettings.asset

@@ -577,7 +577,7 @@ PlayerSettings:
   additionalIl2CppArgs: 
   scriptingRuntimeVersion: 0
   apiCompatibilityLevelPerPlatform:
-    Metro: 1
+    Metro: 3
   m_RenderingPath: 1
   m_MobileRenderingPath: 1
   metroPackageName: MixedRealityToolkit-Unity