Write lo.h when configuring using premake4.
Add a README to the build directory, exclude premake4.exe binary from tarball.

It doesn't fly with the Debian maintainers to include a binary.
However, this helps with building for Visual Studio, so unfortunately
VS users will now have to get premake4.exe from premake's website.  A
work-around would be to pre-generate the VS project files, but the
premake script actually does more than this--it generates config.h and
other files, so we can't do without it.  Therefore, at least a README
has been added to explain this as well as the Android build procedure.
Reformat the main README in Markdown and rename it for the benefit of github.

autogen.sh copies README.md back to "README" for the benefit of
automake.  A bit complicated, but it works.