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/275.wld

@@ -1112,7 +1112,7 @@ S
 The 50-Meter Line~
    You are standing in the middle of the excitement of a bloodball
 game.  To the south is the Warriors' zone, to the north is the
-Raiders'.  Centrefield is east, and the tunnel is west.
+Raiders'.  Centerfield is east, and the tunnel is west.
 ~
 275 8 0 0 0 1
 D0
@@ -1121,7 +1121,7 @@ You see the Raiders' zone.
 ~
 0 -1 27561
 D1
-You see centrefield.
+You see centerfield.
 ~
 ~
 0 -1 27553
@@ -1181,13 +1181,13 @@ The end zone continues.
 S
 #27551
 The Warriors' Zone~
-   You are in the Warriors' defensive zone.  To the north Centre-
+   You are in the Warriors' defensive zone.  To the north Center-
 field, to the south is the end zone.  The field also continues east
 and west.
 ~
 275 8 0 0 0 1
 D0
-You see Centrefield.
+You see Centerfield.
 ~
 ~
 0 -1 27553
@@ -1238,7 +1238,7 @@ The end zone continues.
 0 -1 27550
 S
 #27553
-Centrefield~
+Centerfield~
    This is the center of all action in WarDome.  Flying bodies
 (and body parts) are all around you.  You are standing on a large
 gray skull with glowing eyes and blood stained fangs -- not real of
@@ -1270,7 +1270,7 @@ The 50-Meter line.
 S
 #27554
 The Raiders' Zone~
-   You are in the Raiders' defensive zone.  To the south is Centre-
+   You are in the Raiders' defensive zone.  To the south is Center-
 field, to the north is the end zone.  The field continues east and
 west.
 ~
@@ -1286,7 +1286,7 @@ The field continues.
 ~
 0 -1 27558
 D2
-You see Centrefield.
+You see Centerfield.
 ~
 ~
 0 -1 27553
@@ -1300,7 +1300,7 @@ S
 The 50-Meter Line~
    You are standing in the middle of the excitement of a bloodball
 game.  To the south is the Warriors' zone, to the north is the
-Raiders'.  Centrefield is to the west.
+Raiders'.  Centerfield is to the west.
 ~
 275 8 0 0 0 1
 D0
@@ -1314,7 +1314,7 @@ You see the Warriors' zone.
 ~
 0 -1 27557
 D3
-You see centrefield.
+You see centerfield.
 ~
 ~
 0 -1 27553
@@ -1481,7 +1481,7 @@ Broadway~
    You are on the 400 block of Broadway and as you look at the pot
 holes in the road you realize that city road workers are the same
 everywhere.
-   Broadway continues to the north and south. The armoury is to the
+   Broadway continues to the north and south. The armory is to the
 east and the magic shop is to the west.
 ~
 275 0 0 0 0 1
@@ -1491,7 +1491,7 @@ You see Broadway.
 ~
 0 -1 27569
 D1
-You see the Armoury.
+You see the Armory.
 ~
 ~
 0 -1 27567
@@ -1507,9 +1507,9 @@ You see the Magic Shop.
 0 -1 27568
 S
 #27567
-The Armoury~
-   This is your standard armoury, filled with your average supply of
-of armour and other assorted goodies.
+The Armory~
+   This is your standard armory, filled with your average supply of
+of armor and other assorted goodies.
    Broadway is to the west.
 ~
 275 8 0 0 0 0