(svn r14063) -Codechange: replace some "magic" constants with enumified constants.

src/group_type.h

@@ -11,6 +11,9 @@ enum {
 	ALL_GROUP     = 0xFFFD,
 	DEFAULT_GROUP = 0xFFFE, ///< ungrouped vehicles are in this group.
 	INVALID_GROUP = 0xFFFF,
+
+	MAX_LENGTH_GROUP_NAME_BYTES  =  31, ///< The maximum length of a group name in bytes including '\0'
+	MAX_LENGTH_GROUP_NAME_PIXELS = 150, ///< The maximum length of a group name in pixels
 };
 
 struct Group;