Fix dragon randomness, 1.x slimes, and reset/load on entry.

[AliceLR]

• Reset board on entry and load charset/palette on entry now have an optional setting that makes them work even when re-entering a board from itself (enabled by default).
• Dragons in all DOS versions had a 1/8th chance of making a "dumb" move every time they moved, which was broken in the port. This has been fixed for versions <2.80 and is configurable via the new board setting Dragons randomly move.
• Slime spread speeds between 1.0 and some version between 2.04 and 2.07 used a different algorithm.
• Better slime bug documentation.
• Fixed broken handling for 1.x robot programs <2 bytes.

• Reset board on entry fix and setting hack.