More warnings issued when compiling Avogadro


After porting Kalzium to libavo we noticed about one trillion warnings
while compiling libavogadro. After a short chat with a KDE developer
we learned about a CMake-magic which adds certain CXX-flags when the
compiler is GCC.

I just added these magic lines to our toplevel CMakeLists.txt. You
will notice many compiler warnings now, but IMHO those needs to be
fixed. Benoît told be that especially the virtual dtor warnings are