Makes the tinygettext static library project work on Windows.

There are still a lot of warnings when building but it builds now and I played a game without a crash.
Maybe we could remove the tinygettext headers from the source directory and use those in the include directory for building too.
Removes duplication of header files.
Disables the compiler warnings of tinygettext in visual studio
Reverts tinygettext changes which were required for dynamic linking.
Fixes the debug build on Windows.

We use the same libs for debug and release builds. There's no special debug library with a d suffix.