WIP: AmpGen fixes to compile with gcc 6.2

Added includes for various STL classes, mostly for std::vector which was only implicitly included from algorithm. This worked fine for gcc 4.8 and 4.9 but does not work anymore for gcc 6.2.

Also added plenty of override keywords where applicable to get the extreme number of warnings down due to the -Wsuggest-override flag. Probably missed quite a few and will keep looking.

This is marked as WIP because there seems to be other active AmpGen branches and I am not sure yet which is the smartest way to merge all of them.