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

Codechange: remove the special station/vehicle code from SaveLoad

With the new SLEG_STRUCT it is much easier to embed a struct
in a struct, where the sub-struct has limitations on when it is
being used.
This makes both the code easier to read (less magic) and avoids
the SaveLoad needing to know all these things about Stations
and Vehicles.

Codechange: C++-ify lists for SaveLoad (#9323)

Basically, this changes "SaveLoad *" to either:
1) "SaveLoadTable" if a list of SaveLoads was meant
2) "SaveLoad &" if a single entry was meant

As added bonus, this removes SL_END / SLE_END / SLEG_END. This
also adds core/span.hpp, a "std::span"-lite.

Fix #7925: Reset temporary saveload data at the start of loading a savegame instead of at the end.
Otherwise temporary data may be passed from an aborted load action to the next load action.

(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 r16909) -Fix [FS#2996]: NewGRF stations would be triggering assertions all over the place when using the more advanced station types.
-Change: make (rail) waypoints sub classes of 'base stations', make buoys waypoints and unify code between them where possible.

(svn r15340) -Fix [FS#2121]: changing town road layout in-game caused ugly road networks
-Fix: use a flag instead of TL_NO_ROADS to forbid towns to build roads. The flag is ignored during world generation, so there won't be 'ghost' towns anymore
-Feature: town layout is now stored per town, so it is possible to (manually) set different layout for each town