(svn r5887) -Cleanup: move date related functions, defines and variables to date.[ch]

-Cleanup: fix whitespace related coding style issues in date.[ch]
-Cleanup: make original comments doxygen compatible and remove/change outdated comments

station_cmd.c

@@ -32,6 +32,7 @@
 #include "newgrf_callbacks.h"
 #include "newgrf_station.h"
 #include "yapf/yapf.h"
+#include "date.h"
 
 enum {
 	/* Max stations: 64000 (64 * 1000) */