meson: Fix build system integration bugs, add docs.
This should account for the open issues on !8 and also documents the ninja-options that is introduced to address @ouwerkerk's recommendation. Test suite passes and I continue to be able to build 2048.cpp. I've also validated that ninja-options is passed to ninja when building 2048.cpp, though this was a manual verification.
feature-meson-support in 1 minute and 9 seconds (queued for 2 seconds)2 jobs for