Fix CELL size check when loading OPS saves

src/client/GameSave.cpp

@@ -600,7 +600,7 @@ void GameSave::readOPS(char * data, int dataLength)
 	}
 
 	//Incompatible cell size
-	if (inputData[5] > CELL)
+	if (inputData[5] != CELL)
 		throw ParseException(ParseException::InvalidDimensions, "Incorrect CELL size");
 
 	//Too large/off screen

src/simulation/Gravity.cpp

@@ -157,6 +157,7 @@ void Gravity::gravity_update_async()
 					memcpy(gravx, th_gravx, (XRES/CELL)*(YRES/CELL)*sizeof(float));
 					memcpy(gravp, th_gravp, (XRES/CELL)*(YRES/CELL)*sizeof(float));
 #else
+					// Copy thread gravity maps into this one
 					std::swap(gravy, th_gravy);
 					std::swap(gravx, th_gravx);
 					std::swap(gravp, th_gravp);