Standardize on American spellings.

Full internationalization would be much cooler, but that's never going
to happen.  Given that, this will at least prevent folks from constantly
having to look and switch between typing "armor" and "armour", depending
on which zone each item originated in, etc.

I could flip these either way, but a survey of the current state shows
that about 80% of the mixed cases use the American spellings, while 20%
use the British.  And, most words *only* exist in this data in their
American forms.  So, it seems the majority prefer these spellings.

In case anyone likes trivia:
* The most common mixed words in here were "armour" and "colour", each of
  which occured about half as often as "armor" and "color", respectively.
* The most British word in here was "theatre" (including other forms),
  which occured about twice as often as "theater".

This stanardizes all of these (and other forms of these same words):
* armour -> armor
* colour -> color
* favour -> favor
* honour -> honor
* civilise -> civilize
* centre -> center
* theatre -> theater
* defence -> defense
* offence -> offense
* realise -> realize

lib/world/wld/248.wld

@@ -146,7 +146,7 @@ S
 A Fine Path Through the Elven Forest~
    On both sides of this path is doors.  Over the eastern door is a sign
 telling you this must be the weapon shop, and over the western door is a
-similar sign telling you it's the armoury.
+similar sign telling you it's the armory.
 ~
 248 0 0 0 0 3
 D0
@@ -167,10 +167,10 @@ D3
 0 -1 24811
 S
 #24810
-The Elven Armoury~
-   On the walls of this large room are fine elven armours hanging.  A few other
+The Elven Armory~
+   On the walls of this large room are fine elven armors hanging.  A few other
 odds and ends lay about that are required for the bending and pounding of the
-armour.
+armor.
 ~
 248 8 0 0 0 0
 D3