Added trim() call to work around mystery bug where whitespace gets appended to single...

Added trim() call to work around mystery bug where whitespace gets appended to single or double-quoted string tokens; without it we ended up reading in the extra quote on the end as if it were part of the string.

Examples from reading in extension .i18n files:
-    'quiz_reset' => 'Reset',
+    'quiz_reset' => 'Reset"',

-    'very-special-message' => 'Aren\'t I special?',
+    'very-special-message' => 'Aren\'t I special?"
+ ',

-    'nss-db-error' => 'Error reading from authentication database',
+    'nss-db-error' => 'Error reading from authentication database\'',