fix #8: Enhance hex file loading robustness and cross-platform compat…

[markroth8]

Library Fix

• In src/vrEmu6502.c, updated vrEmu6502Reset() to initialize vr6502->currentOpcodeAddr = 0xffff;.

Test Runner Fixes

• Robust Parsing: Refactored readHexFile to use manual parsing with memcpy and explicit null-termination via memset on a reusable temporary buffer.
• Binary Mode: HEX files are now opened with "rb" to ensure consistent behavior across platforms.
• Initialization Sync: Initialized lastPc = 0; in main() to ensure it does not match the library's initial 0xffff.
• MSVC Compatibility: Fixed signed/unsigned comparison warnings and other minor MSVC-specific issues to ensure a clean build with /WX.

Verification Results

All 11 tests now pass on Windows:
100% tests passed, 0 tests failed out of 11

Tested with ctest -C Release

[markroth8]

Fixes #8

[markroth8]

Actually, hold on, I may have incorrectly diagnosed the reason for the failure.

[markroth8]

Test Runner Fixes

• Fix premature trap detection when memory state is pre-initialized (as is the case in Windows), causing lastPc == PC before the test even begins!

Verification Results
All 11 tests now pass on Windows:
100% tests passed, 0 tests failed out of 11

Tested with ctest -C Release

[visrealm]

Thanks