NEVERHOOD: Made multi-line function-line macros safer

Wrapped the code in the SetUpdateHandler(), SetMessageHandler(),
SetSpriteUpdate(), SetFilterX(), SetFilterY() and NextState()
macros in "do { ... } while (0)". Otherwise you may fool yourself
because in "if (condition) macro();" the "if" will only cover the
first statement of the macro.

CID 1022340, 1022341, 1022342, 1022343