Chairs

Fix:

• #2 Getting out of a chair no longer places you back where you were standing when you clicked on it
• #3 You can sit "on" (in) upside down stairs

Changes:

• Will now prevent the player from entering chair with a block on top of it or if the player is already sitting.
• Wll now teleport you back to your last location when you exit the chair only if the chair was not moved by a piston, if it had, it will teleport you on top of the stair.