Setup CI and CMake-based build system

[szalpal]

Summary

Hi! I came upon this project and I really like it. I'd like to use dds for one of my pet projects. Since I'll be adding some updates to dds, I figured I can contribute to parent repository. This is my first contribution here, please let me know about any comments you might have - I'd gladly explain everything.

I wanted to start from setting up a CI with github actions and creating more modern build system. This PR adds the CI and CMake routines. Additionally, I'm submitting 2 test fixes that I uncovered while setting up the CI. Please find everything in details below. All changes are properly split into commits, to make later maintenance robust.

Lastly, there are 2 sharp edges:

1. Currently macOS and Windows builds had to be build with -Werror turned off, since there are many warnings in these builds. Hopefully we can resolve them later.
2. I had to turn off tests for Windows build, since they fail. Unfortunately, I don't have a Windows system (nor do I know anything about it), therefore it's hard to me to fix those tests at this stage.

Setup CI and CMake-based build system

Adds a modern CMake build system alongside the existing platform-specific Makefiles, with CTest integration and GitHub Actions CI.

CMake build system (CMakeLists.txt)

• Builds the dds shared/static library (alias dds::dds) with find_package support via cmake/ddsConfig.cmake.in
• Supports all five threading backends (OpenMP, STL, Boost, GCD, WinAPI) as options, with platform-appropriate defaults applied automatically when none are explicitly selected
• Exposes DDS_BUILD_TESTS and DDS_BUILD_EXAMPLES to build dtest and the 13 example programs
• Enables LTO for Release builds, full warning flags, and linker hardening on Linux shared builds
• DDS_WERROR option (default ON) controls -Werror//WX, making it easy to turn off for platforms with noisy compilers

CTest integration

• test/CMakeLists.txt: 6 tests covering all five dtest solver modes (solve, calc, par, dealerpar, play) plus a GIB-format calc test
• examples/CMakeLists.txt: 13 tests, one per example program
• Both use FAIL_REGULAR_EXPRESSION to detect failures, since neither dtest nor the examples return a non-zero exit code on failure

GitHub Actions CI (.github/workflows/ci.yml)

Five jobs run in parallel on every push/PR to main and develop:

Job	OS	Library	Threading
Linux GCC	ubuntu-latest	shared	OpenMP + STL
Linux Clang	ubuntu-latest	shared	OpenMP + STL
Linux GCC / Boost	ubuntu-latest	static	Boost + STL
macOS	macos-latest	shared	GCD + STL
Windows MSVC	windows-latest	static	WinAPI + OpenMP + STL

macOS and Windows build with -DDDS_WERROR=OFF. Windows tests are currently skipped pending fixes.

Source fixes required for clean compilation

• src/Moves.cpp: replaced two UTF-8 characters with ASCII equivalents (caused MSVC parse errors)
• src/TransTableL.cpp: corrected array definition in function signature (ill-formed under strict compilers)