Remove battle staging details from README

Removed section about battle staging and conditions.

README.md

@@ -37,40 +37,3 @@ menu.
 
 **3D-BTL** is on by default and is independent of **VOXEL**: battles draw
 on the world whether or not the free-roam camera is pitched over.
-
-## Where a battle is staged
-
-The mod looks for the nearest clearing shaped like this, where every `x` is
-a cell the player could walk onto — the two mons three cells apart down the
-middle, with a one-cell apron so the camera looks across floor rather than
-into a wall:
-
-```
-x x x
-x O x     O   the enemy's mon
-x x x
-x x x
-x P x     P   your mon
-x x x
-```
-
-Indoors, in a corridor or in a cave there is often no room for that, so the
-search relaxes to the same three-cell gap with the apron given up:
-
-```
-O
-x
-x
-P
-```
-
-If neither will fit — and on a map with no open ground at all, or on a
-machine with no depth-buffer support — the battle draws exactly the way it
-always did. Water counts as open ground while you are surfing and not
-otherwise, and warp tiles never count, so a fight is never framed in a
-doorway.
-
-Two of those keys are taken off the engine: `3` was **TILT** and `5` was
-**GBC FX**. Neither is reachable by key while this mod is enabled, and both
-are still on the OPTIONS menu. Pressing `3` also switches both off — they
-fight the diorama, and it is the way back from having left one on.