(svn r1407) -Codechange: changed a lot around _stations, _vehicles, _towns and _industries

(in prepare of dynamic arrays):
  - DEREF_XXX is changed into GetXXX
  - All direct call are directed via GetXXX
  - struct Industry has now an index-field
  - ENUM'd some stuff
  - Replaced home built loops with FOR_ALL_XXX
  - Added _stations_size, _vehicles_size, ... which gives the length of the
    array (which will be dynamic in the near future)
  - Changed lengtof(XXX) to _XXX_size (e.g. _stations_size)
  - Removed all endof(XXX) (because mostly it was part of a FOR_ALL_XXX)
  - Made the sort-functions of all 4 dynamic
  - Made all 4 Initialize functions more of the same
  - Some minor tab-fixing and stuff
  (tnx to Tron for proof-reading my 100kb patch ;))

  Note for all: please do NOT directly call _stations, _vehicles, _towns and
  _industries, but use the right wrapper to access them. Thank you.
  Ps: please also do not use 'v++', where v is of type Vehicle *.

vehicle.h

@@ -408,9 +408,6 @@ byte GetDirectionTowards(Vehicle *v, int x, int y);
 #define BEGIN_ENUM_WAGONS(v) do {
 #define END_ENUM_WAGONS(v) } while ( (v=v->next) != NULL);
 
-#define DEREF_VEHICLE(i) (&_vehicles[i])
-#define FOR_ALL_VEHICLES(v) for(v=_vehicles; v != endof(_vehicles); v++)
-
 /* vehicle.c */
 enum {
 	NUM_NORMAL_VEHICLES = 2048,
@@ -419,6 +416,18 @@ enum {
 };
 
 VARDEF Vehicle _vehicles[NUM_VEHICLES];
+VARDEF uint _vehicles_size;
+
+VARDEF SortStruct *_vehicle_sort;
+
+static inline Vehicle *GetVehicle(uint index)
+{
+	assert(index < _vehicles_size);
+	return &_vehicles[index];
+}
+
+#define FOR_ALL_VEHICLES(v) for(v = _vehicles; v != &_vehicles[_vehicles_size]; v++)
+#define FOR_ALL_VEHICLES_FROM(v, from) for(v = GetVehicle(from); v != &_vehicles[_vehicles_size]; v++)
 
 VARDEF Order _order_array[5000];
 VARDEF Order *_ptr_to_next_order;