Another Quick Fix on Pickup

Added more checks in PickupKey1 and PickupKey2

Found an issue where if a box was wrongly tagged/scripted, i.e. tagged
Pickup2 but had the script PickupMouse1. NullReferenceExceptions would
be thrown as PickupKey2 would be looking for the script PickupMouse2 on
at box, which of course doesn't exist.

Added more checks the prevent the exception being thrown, however if
things are wrongly tagged/scripted pickup wont work as intended anyway.
Revert "Another Quick Fix on Pickup"

This reverts commit 89898d06b389b7dc8405f43f38c1f8052dee8b0b.
Quick Fix On Pickup

Found an issue. There was a box in the top world tagged as "Pickup2" so
it would check for the script PickupMouse2. But that box had
PickupMouse1 script instead. Thus NullReferenceExceptions were thrown.

Fixed the tagging and added more checks to prevent the exceptions.
However if things are not tagged/scripted correctly Pickup wont work as
intended.
Merge branch 'master' of https://github.com/dawner/downsideup_upsidedown