iOS: Vulkan support

Implemented Vulkan Support.
Use DisplayServer for rendering and input handling
Use single view for rendering in both GLES2 (not supported yet) and Vulkan
Use @available checks where it's required (otherwise compiler would fail compilation)
Simulator checks

platform/iphone/detect.py

@@ -143,6 +143,9 @@ def configure(env):
         else:
             env.Append(CCFLAGS=["-fno-exceptions"])
 
+    # Temp fix for ABS/MAX/MIN macros in iPhone SDK blocking compilation
+    env.Append(CCFLAGS=["-Wno-ambiguous-macro"])
+
     ## Link flags
 
     if env["arch"] == "x86" or env["arch"] == "x86_64":