[r1271] Looking up doesn't seem to clamp pitch properly

[Nash]

Look straight up (90 degrees), then push the mouse further up. It does seem to clamp the pitch. However, when moving the mouse down, the view pitch remains at 90 degrees upwards.

You'd have to move the mouse down a few times before the view pitch finally starts to update again.

[Enjay]

The recent pitch clamping code seems to have a few wrinkles. This ZDoom bug where vertical looking becomes disabled when you transition from one map to the next has migrated across to GZDoom with the recent updates.

[Gez]

Fixed.