Several more tweaks/fixes

- Missing special node opcodes
- Pass the party's (or in combat, the active character's) current location to special nodes triggered by timers
- Fix the set pointer node
- Fix terrain palette not correctly registering clicks while scrolled down
- Fix sheets not correctly being copied from the temporary files folder
- Fix monster abilities not being loaded from new scenarios
- Fix custom sheets not being reloaded if they have changed
- Documentation tweaks

doc/editor/appendix/Specials.html

@@ -1689,7 +1689,8 @@ both in town and outdoors, but the first few only work in town. For these nodes,
 values have slightly different meanings than before:</p>
 <dt>Extra 1a, Extra 1b, Extra 2a, Extra 2b:</dt><dd>For each of these specials, Extra 1a
 and Extra 1b are the top and left of the rectangle. Extra 2a and Extra 2b are the bottom
-and right of the rectangle.
+and right of the rectangle. Note that this is the reverse of standard coordinate order -
+Y coordinate first, then X coordinate.
 <p>The default values of Extra 2a and Extra 2b are -1. If you want the effect to only
 apply to one space (and not a whole rectangle), leave Extra 2a and Extra 2b at -1. In this
 case, the node only affects the space specified by Extra 1a and Extra 1b.</dd>