(svn r2962) - const correctness for all Get* functions and most Draw* functions that don't change their pointer parameters

- change a lot of byte player types to PlayerID
- beautify header files, same "#endif /* filename */" ending

currency.h

@@ -26,4 +26,4 @@ uint GetMaskOfAllowedCurrencies(void);
 uint GetCurrentCurrencyRate(void);
 void CheckSwitchToEuro(void);
 
-#endif
+#endif /* CURRENCY_H */