Signs

1. Fixed exploit(s) with setting images and updating other players' signs

1. Fixed the stupid TEXT_ALIGN_TOP/TEXT_ALIGN_BOTTOM switch

1. Fixed map cleanup (again)

1. Fixed signs not sending data on respawn during map cleanup

1. Fixed physgun freezing issues

1. Added PostCleanupMap hook to respawn perm signs
2. Fixed players being able to edit perm signs
3. Added some default FPP behaviors, such as allowing players to physgun the signs automatically

Initial version.