(svn r12293) -Feature: Ability to change aircraft speed factor, from so
called 'realistic' (matching other vehicles) (1/1) to original TTD
speed (1/4). Note this option defaults to original TTD speed.

(svn r12230) -Codechange: [autoreplace] made a function to detect if a vehicle needs autorenewing
This will remove duplicated code and ensure that the check is consistent

(svn r12144) -Codechange: Adjust aircraft slowing algorithm so that very fast
aircraft slow down more rapidly than slower aircraft. This prevents them
from reaching the end of the runway at high speed, and also stops slow
aircraft from slowing down too much at the start of the runway.

(svn r12134) -Change: count the number of ticks a vehicle was running this day to calculate running cost
-Fix [FS#1739]: vehicle profit is now counted with 8bit fract, so it is now shown properly in the vehicle details window

(svn r11935) -Fix (r11875)[FS#1672]: autosend aircraft to hangar for replacement check inverted the check for autorenew
Now it triggers when renew setting is on and only if it's on
Note: aircraft already enroute to hangars due to this bug will still go there. They will only head there once though

(svn r11916) -Codechange: use enums from VehicleViewWindowWidgets instead of constants
-Fix: refit button widget was not correctly updated

(svn r11875) -Fix: automatically sending aircraft to depot for autoreplace/renew is now triggered by the correct conditions
Now it triggers by the following conditions:
- aircraft is old enough for renew or needs to be autoreplaced
- player has 2*cost of new aircraft+autorenew money (we don't want to send many aircraft to hangars when there is only money for replacing one)
- aircraft has no hangars in it's order list
- new aircraft is buildable (imagine autorenewing a retired design)
This triggers right after a helicopter takes off or when a plane touches the ground while landing

Another effect of this change is that this functionality no longer generates network traffic

(svn r11822) -Codechange: Replaced fixed size custom name array. Names are now attached to their object directly and there is
no limit to the amount of names.
-Fix: NewGRF engines could not be renamed.

(svn r11546) -Fix[FS#1496]: If ever the air/heli port is suddenly not available while the "chopper" is descending, just go back into flying.
The code should have been better written, but in respect of newgrf_port branch, i prefer minimalist intervention

(svn r11523) -Codechange: Move the CHANCE macros to core/random_func.cpp cause they depend on Random()
-Codechange: Convert the CHANCE macros to functions and rename them fitting to the naming style

(svn r11332) -Fix: vehicles getting a value of 0 on construction.
-Fix: assertion when selling vehicles.

(svn r10770) -Codechange: use the pool item class as super class for the vehicle struct.
-Codechange: do not force "special" vehicles to be allocated in the low 1024 vehicle slots and non "special" vehicles in the rest of the slots.

(svn r9684) -Fix (r9683): Remove vehicles from the station loading list instead of adding
them again when they leave, and add a v->LeaveStation() call for aircraft.

(svn r9543) -Fix [FS#691]: Split up STR_ENGINE_NOT_BUILDABLE into four strings so it can be
translated properly and remove "buildable", since it isn't actually a word.

(svn r9299) -Fix (FS#675,FS#660): Small micro-movements on airports (of <4 pixels) caused odd aircraft movements. On oilrigs, this caused a full crash as movement would take helicopter out of airport/station tile.
Corrected by maneuvering aircraft directly over these tiny movements, rather than relying on movement by changing facing.