(svn r21933) -Codechange: Split cur_order_index into cur_auto_order_index and cur_real_order_index to keep track of the current real order in an unambiguous way.
-Fix [FS#4440]: Automatic orders behave now stable wrt. service orders and are not added or removed depending on the need of servicing.
-Fix: Various other issues with automatic orders, e.g. vehicles getting stuck with "no orders" when there are automatic orders at the end of the order list.

(svn r20034) -Fix [FS#3896] (r14869): road vehicles could get crashed twice in a tick
In RoadVehicleController at tick N a road vehicle gets a j of slightly less
than adv_speed. In tick N+1 RoadVehCheckTrainCrash is called, then the road
vehicle gets a j of slightly more than adv_speed. This causes a second call
of RoadVehCheckTrainCrash. If in tick N the road vehicle moved onto a level
crossing and a (maglev) entered that tile at the same tick, in tick N+1 the
road vehicle would be crashed twice.

(svn r18481) -Codechange: unify the curve pathfinder penalty defaults; 0.01 tile won't make a dent, 3 tiles might be a bit too much
-Feature-ish: make maximum pathfinder penalties for finding depots customisable, also increase it slightly to 20 tiles worth of penalties.

(svn r18404) -Codechange: link drive through stops better together
-Feature: make penalty for road stop occupancy user configurable
-Fix [FS#1944]: road vehicles would not pick an empty drive through stop. Now they will *if* the penalty for driving around is less than the occupancy penalty
-Fix [FS#1495]: long (articulated) road vehicles could block loading of others when the following road vehicle already got 'permission' to go to the next bay even when it could not reach it
-Change: improve the throughput of the drive through road stops by letting them stop closer together

(svn r17897) -Fix [FS#3255]: CB15 and CB36 (capacity) were not always called when they should.
-Codechange: Move capacity calculation to a single function for all vehicle types, so the behaviour can be kept consistent easier.