This change makes it possible to add a new backend without
changing any of the core files. It also gets rid of some
hacks (like -export-dynamic for the binary) by putting all
core SyncEvolution code into a library.
The transition is not quite complete: there are still
some lists of existing backends, which will be removed
soon. EvolutionSmartPtr.h and EvolutionSyncSource depend
on Evolution/GNOME libs, which forces all backends to
use the right -I flags.
git-svn-id: https://zeitsenke.de/svn/SyncEvolution/trunk@684 15ad00c4-1369-45f4-8270-35d70d36bdcd
