Bump license year for SDL and AS.

Source/ThirdParty/LICENSES

@@ -1,8 +1,5 @@
-AngelScript license
--------------------
-
 AngelCode Scripting Library
-Copyright (c) 2003-2011 Andreas Jonsson
+Copyright (c) 2003-2018 Andreas Jonsson
 
 This software is provided 'as-is', without any express or implied
 warranty. In no event will the authors be held liable for any
@@ -565,7 +562,7 @@ SDL license
 -----------
 
 Simple DirectMedia Layer
-Copyright (C) 1997-2016 Sam Lantinga <[email protected]>
+Copyright (C) 1997-2019 Sam Lantinga <[email protected]>
 
 This software is provided 'as-is', without any express or implied
 warranty.  In no event will the authors be held liable for any damages