Feature: [NewGRF] Related Act2 objects for airports and airport tiles.

Airports are similar two stations and industries, both of which have the town as related object.
Airport tiles are similar to industry tiles, which have the industry as related object.
This seems a sensible structure, so let's make it Airport Tile -> Airport -> Town.

Add: [NewGRF] Inspection window for airports.

As as the station window combines all station types, accessing the
debug view is via the parent of the airport tile only.

Codechange: automatic adding of _t to (u)int types, and WChar to char32_t

for i in `find src -type f|grep -v 3rdparty/fmt|grep -v 3rdparty/catch2|grep -v 3rdparty/opengl|grep -v stdafx.h`; do sed 's/uint16& /uint16 \&/g;s/int8\([ >*),;[]\)/int8_t\1/g;s/int16\([ >*),;[]\)/int16_t\1/g;s/int32\([ >*),;[]\)/int32_t\1/g;s/int64\([ >*),;[]\)/int64_t\1/g;s/ uint32(/ uint32_t(/g;s/_uint8_t/_uint8/;s/Uint8_t/Uint8/;s/ft_int64_t/ft_int64/g;s/uint64$/uint64_t/;s/WChar/char32_t/g;s/char32_t char32_t/char32_t WChar/' -i $i; done

(svn r19353) -Codechange: use static objects for the airport statemachines instead of new/delete at the start/end of the game
-Codechange: store the fta in AirportSpec

(svn r19299) -Codechange: store the most compatible ttd airport type in AirportSpec
-Fix: [NewGRF] return the ttd airport type in station var 0xF1