BUILD: Add scripts to parse all Makefile.am and build with CMake.

I assume you are still not interested by CMake, but I've got a much cleaner solution than last time regarding CMake building.

Both build systems can even cohabitate, as long as the external dependencies or compilation flags are not modified (in which case one would have to modify both build description files).
The sources and target definitions can be kept in Makefile.am and CMake is parsing them.

Also, as a big plus for CMake, the configure step is much quicker, or at least for me, running on Debian/Linux. For some reason autotools is taking ages to figure out what or where Boost libraries could be found.

Regarding cross-platform, I could not test on anything else than Debian/Linux but CMake begin cross platform, I think it's only a matter of tweaking (especially compilation flags) to get this change working everywhere.