War on -Werror, part 12: explicit bool usage.

It may save a few cycles, but it's best to be
explicit on boolean operations, especially with
ASSERT.

src/ScreenNameEntry.cpp

@@ -128,7 +128,7 @@ ScreenNameEntry::ScreenNameEntry()
 			ss.m_vpPossibleSongs = ss.m_vpPlayedSongs;
 			ss.m_pStyle = GAMESTATE->GetCurrentStyle();
 			ss.m_playMode = GAMESTATE->m_PlayMode;
-			ASSERT( ss.m_vpPlayedSongs[0]->GetAllSteps().size() );
+			ASSERT( ss.m_vpPlayedSongs[0]->GetAllSteps().size() != 0 );
 			StepsType st = GAMESTATE->GetCurrentStyle()->m_StepsType;
 
 			FOREACH_PlayerNumber( p )