Street Rod SDL3 port v0.1.0

First public build of the Street Rod SDL3 port (Windows x64).

Unzip srport-v0.1.0-win64.zip into the folder that holds your game files in a folder named Game, then start
Street Rod.exe (the launcher) or srport.exe. The original game files are not included; you can get the game
for free from the copyright owner: https://www.streetrodonline.com/downloads/.

Download	Mode	Needs from your game folder
srport-v0.1.0-win64.zip	VGA 320×200, 16 colours; PC speaker	SR.EXE, LIB1, LIB2, HOT_DATA; for the data disk cars datadisk\SRSE.EXE, LIB1, LIB2, HOT_DATA (Street Rod SE)

• A faithful C reimplementation of SR.EXE: the title, the driver's licence, the newspaper and its ads, used
  cars and auto parts, haggling, the garage (engine bay, gearbox, tyres, tune-up, paint and customising), the gas
  station, Bob's Drive-In with its opponents, bets and pink slips, drag and road races, the police, breakdowns,
  the summer calendar, saved games, the hall of fame and the ending.
• Launcher (Street Rod.exe): game folder, the data disk's 25 cars (Street Rod SE, the default) or the
  original cars, the game's own switches (demo, races that drive themselves, no mouse), window size and full
  screen; the keys of the game at a glance.
• Added: A / Z shift up and down in races. Space, the joystick button and the mouse still shift as in the
  original.
• The game paces itself by its own timer, as the original did, so it runs at its original speed.
• The PC speaker is emulated, including the bit-banged noise effects. Copy protection and disk handling are
  removed. A gamepad works as the joystick.
• The game folder must be writable: saved games (HOTROD1.SAV …) and the hall of fame (hall_dat) are saved
  there; the data disk's games in datadisk.
• First release: please report any difference from the original in the issues.
• The zip includes SDL3.dll with libiconv-2.dll, and the launcher's wxWidgets DLLs with the libraries they
  load. Their licences and sources are listed in licenses/THIRD-PARTY.txt.

See the README for all changes from the original and for build instructions.