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/obj/247.obj

@@ -9,7 +9,7 @@ A pewter candlestick is standing here.~
 E
 candlestick~
    It is a rather old-looking three-armed candlestick made from pewter.  Its
-candles are a yellowish white colour.
+candles are a yellowish white color.
 ~
 #24701
 cross~
@@ -115,7 +115,7 @@ A cloak as black as the very night lies on the ground.~
 5 500 50 0 0
 E
 shadow cloak~
-   It is pure black in colour -- as pure black as the heart that wears it.
+   It is pure black in color -- as pure black as the heart that wears it.
 ~
 A
 2 1
@@ -298,7 +298,7 @@ The black robe of the undead is spread out on the floor before you.~
 10 240 24 0 0
 E
 black robe~
-   It is jet black in colour and seems to radiate evil.
+   It is jet black in color and seems to radiate evil.
 ~
 A
 12 50