(svn r7565) -Codechange: Rework DEBUG functionality. Look for appropiate debugging levels to
use in debug.h. grfmsg() is now used as a specific debug-function for grf.

(svn r6770) -Codechange: Make the airport checking a bit stricter...fix unnoticed errors:
Commuter (20): invalid use of terminal group designator; since all other options
goto position 2 and no additional blocks are checked, simplify state
Intercontinental (23, 30): no extra states are needed since all options go to
position 70 and 31 unconditionally
Intercontinental (31): invalid use of more-options-to-follow (255)

(svn r6769) -Codechange: Minor syntax, const correctness, variable localization, coding
style changes to airport code, and cleanup of airport.c. Should not change
any functionality.

(svn r6768) -Cleanup: For airports change *Airport to *apc (variable naming coding style
conformance (AirportFTAClass), *FA to *apFA (to better reflect its type
AirportFTAbuildup), and ->next_in_chain into ->next.

(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-Cleanup: make original comments doxygen compatible and remove/change outdated comments

(svn r5346) - Feature: Add 4 new airports. 2 for aircraft, 2 for helicopters.
Commuter airport: Small. 5x4. 3 terminals, 2 helipads.
Intercontinental: massive. 9x11. 8 terminals, 2 helipads, 4 runways.
Helidepot: a small heliport with a depot for helis only.
Helistation: a large heliport with 3 helipads and a depot.

(svn r3181) -Bracing
-Indentation
-Whitespace
-DeMorgan's Law
-Test with NULL or 0 for non-booleans
-'\0' instead of 0 for chars
-Remove redundantly redundant comments (like DoFoo(); // Do foo)
-Join multiple short lines with a single statement
-Split single lines with multiple statements
-Avoid assignments in if

(svn r3078) Some more stuff, which piled up:
- const, whitespace, indentation, bracing, GB/SB, pointless casts
- use the trinary operator where appropriate
- data types (uint[] -> AcceptedCargo, ...)
- if cascade -> switch
- if (ptr) -> if (ptr != NULL)
- DeMorgan's Law
- Fix some comments
- 0 -> '\0', change magic numbers to symbolic constants

(svn r1440) -Feature: Allows more flexible airport layouts now, as the number of
terminals in every group can be freely chosen
-Codechange: AT_OILRIG is now 15, so that new airports can be added
easily.

(svn r223) -Fix: Const correctness and miscellaneous fixes. Thank you Tron for your diligent fixing of warnings (and some possibly bugs) (Tron)
-CodeLayout: Remove trailing spaces and Windows linebreaks

(svn r70) -Fix: typo in english.txt
-Add some debug messages for misc=1

(svn r66) -Fix Station list updated on station deletion/station rename
-Changed debug messages to comply with DEBUG(name, level) heuristics