[Ogre] Optional Ogre tread damage rule

[David Morse]

Optional incremental Ogre tread damage rule:

When an Ogre has taken tread damage, but not enough to slow it down to 
the next slower movement speed, and it attempts to spend that movement 
point, the controlling player has to roll a number less than or equal 
its remaining treads to move.

Example: An Ogre Mark V has lost 6 treads, leaving 14 treads between it 
and M2.  On a turn when it tries to move three hexes, roll a 20-sided 
die, and if the result is 15-20, the Ogre's attempt to spend its 3rd 
movement point fails, leaving it stuck wherever it was after 2 movement 
points.

Fine print: the reason its a 20-sided die is because the Mk V originally 
had 20 treads at M3.  If it'd been a Mark III, with 9 of 15 treads at 
M3, it would have had to roll a 1-9 on a 15 sided die.  (I guess 
(d30)/2, since d15 don't exist).

I suppose this 'orribly screws Ogres.  The idea first came to me though 
when I was commanding a Fencer against a Mark III.  I could go for a 
shot at range 5 versus secondaries, probably leaving 2 alive and losing 
2.5 precious missile racks to the inevitable range-2 retaliation, or I 
could really gamble and go for treads.  If I hit with 3 out of 4 
missiles against the treads, then I'd knock him down to M2, and clearly 
win the duel, but since the odds of that were under 5%, I'd probably not 
damage ANY of his guns, have him move up to range 2, and wallop me 
silly.  If by partially damaging his treads at range-5 I got a 
statisical chance that he'd not be able to close to all-important 
range-2, that'd probably tip the balance in favor of my shooting at treads.

In practice, I lost my nerve and wandered off to beat on some straggly 
heavy tanks...always a good option with a Fencer.