initial attempt at scrolling maps.  Followed code at: http://roguebasin.roguelikedevelopment.org/index.php?title=Complete_Roguelike_Tutorial,_using_python%2Blibtcod,_extras_scrolling_code
It's an enhancement of the part 10 tutorial: http://roguebasin.roguelikedevelopment.org/index.php?title=Complete_Roguelike_Tutorial,_using_python%2Blibtcod,_part_10_code
I thought I picked up all the changes, but things aren't working.  the player and enemies are at x+1 and y+1 relative to the actual map when CAMERA_WIDTH/HEIGHT = MAP_WIDTH/HEIGHT. When the camera is smaller than the map (to force scrolling) nothing shows up at all.
The mapscrolling example works though, so it's definitely related to changes I've probably made.
scrolling is working!  fixed errors in Object.clear() and a render_all error that shouldn't have been using camera_x/y.  Also had an error with the way Panel Height was defined. In the tutorial it's set to a value, but I had set it equal to SCREEN_HEIGHT - MAP_HEIGHT. Had to change MAP_HEIGHT to CAMERA_HEIGHT.
Works ok, but gets sorta slow on bigger maps.