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/201.wld

@@ -108,7 +108,7 @@ footprints prints foot~
 ~
 E
 dust~
-   It is powdery-looking and grey in colour.
+   It is powdery-looking and grey in color.
 ~
 S
 #20105
@@ -140,7 +140,7 @@ Konolua Seashore
 0 20100 20106
 E
 sand grain grains~
-   Coarse grains of sand fills this beach.  They are a rich yellow colour and
+   Coarse grains of sand fills this beach.  They are a rich yellow color and
 are rough in texture.
 ~
 S
@@ -642,7 +642,7 @@ S
 T 20105
 #20122
 On a Sandy Path~
-   The sandy path is made up of coarse sand, a deep yellow colour - wet from the
+   The sandy path is made up of coarse sand, a deep yellow color - wet from the
 waves coming from the east.  To the north is a grey, solemn cliff guarding
 Konolua beach while the path continues south.
 ~