Feature - save/continue

Add a save feature. The game will automatically save at designated points through out the game so you continue back where you left off.

Save points occur (semi-spoilers):
Entering the mansion
Entering the room with the statue door missing an eye
Upon exiting the elevator
Upon exiting the air vent
Upon exiting the operating room
Upon starting the step-tracker

Also add mouse lock so that the cursor does not accidentally leave the window if you play in windowed mode.