REBASEME: Add a .gitignore
Add headers to CMakeLists.txt

This is a noop for the standard CMake build process, but it actually
displays all headers in QtCreator.
CMake: Auto-detect pthread and hwloc

This is the preferred CMake way of handling libraries. As a bonus, we
get informative error messages when necessary dependendies are not found.
CMake: A more portable way of defining CXX flags

Of course we'd have to define flags for other compilers, but at least we
won't pass non-applicable flags.
CMake: Remove cruft

Nonworking tests are unused. Link directories should be handled by
find_package() & co.
REBASEME: Auto-detect BLAS and LAPACK as well
CMake: Don't warn about variable size arrays
Fix all 'unused argument' warnings in complete build
CMake: Enable debug mode in Debug build types

Additionally, commented two broken assert statements exposed by
PHEET_DEBUG_MODE.
Convert all windows line endings to unix newlines

Just to stay consistent.