Windows build improvements from bzip2-windows
As described in #17 (closed), here are the patches from my bzip2-windows project related to improvements to the build process (patches 1 to 4 from the list).
I've also fixed an issue related to the move of the test files in commit f6f3326c, added some .gitignore entries and updated README.md.
The README only describes Windows builds using nmake and the makefile.msc file at the moment. Something should be added about using Meson, but that's not something I'm familiar with.