fix VC7 warnings

stepmania/src/LuaManager.cpp

@@ -119,7 +119,7 @@ bool LuaManager::PopStack( bool &out, lua_State *L )
 	if( L == NULL )
 		L = LUA->L;
 
-	out = lua_toboolean( L, -1 );
+	out = !!lua_toboolean( L, -1 );
 	lua_pop( L, 1 );
 	return true;
 }
@@ -129,7 +129,7 @@ bool LuaManager::PopStack( float &val, lua_State *L )
 	if( L == NULL )
 		L = LUA->L;
 
-	val = lua_tonumber( L, -1 );
+	val = (float)lua_tonumber( L, -1 );
 	lua_pop( L, 1 );
 	return true;
 }

stepmania/src/PrefsManager.cpp

@@ -838,7 +838,10 @@ public:
 			lua_pushnil( L );
 		}
 		else
+		{
 			pPref->PushValue( L );
+		}
+		return 1;
 	}
 	static int SetPreference( T* p, lua_State *L )
 	{