Fix some warnings.
- rP24553 added 'override' to a method in ShaderProgram.cpp. This adds it to the rest.
- BinarySerializer.cpp had custom JS includes, because putting those in ScriptExtraHeaders failed. The cause is that gloox leaves "#define lookup" up. This has been reported upstream, and fixed here.
- VS17 complains about an uninitialised variable, though the usage is safe.
Differential Revision: https://code.wildfiregames.com/D3916