0.3.8 - Widescreen special stages, 4:3 lobby

Widescreen special stages, and a clean 4:3 lobby.

• Special stages are widescreen (Issue #18): the tube now fills the whole widescreen picture instead of dropping to 4:3. The special stage draws its tube as SH-2 polygons, and its rasterizer cannot draw left of the screen edge, so the tube is projected further right and moved back on the host side. Game logic is unchanged: the 68K RAM matches a 4:3 run on every frame. The stage's own picture matches 4:3 apart from occasional one-pixel differences along polygon edges, because widescreen clips those polygons less.
• The lobby stays 4:3 (Issue #13): in WORLD ENTRANCE, the area where you pick characters and take the catapult, widescreen showed scenery from neighbouring areas in its narrow rooms, switched palettes too early, and lost chunks during the catapult launch, sometimes even in the middle of the picture. The lobby is now shown exactly as in 4:3, with black side bars. Every level stays widescreen.

Validation: all 24 CTest cases pass on the MinGW build. That includes 4 new widescreen tests: special-stage lockstep, the special stage going widescreen, the special-stage centre against 4:3, and the lobby staying 4:3. It also includes the 36,000-frame lockstep and golden-frame runs. The packaged Windows build passed the five ROM startup tests with a system-only PATH. The Android APK has not been tested on a device for this release.

Windows x64 and Android arm64-v8a/x86_64 builds are included. Android uses version code 11 and the same signing certificate as 0.3.7 for in-place updates. As before, the APK is debug-signed with Release native code.

You must supply your own Knuckles' Chaotix (Japan, USA) ROM. No ROM image or game assets are included. Details: Issue #18 notes, Issue #13 notes.