This diff adds a new loader class SvnLoaderFromRemoteDump enabling
to load svn repositories in a more efficient way. The loader is based
on the creation of dump files generated with the svnrdump tool. Using
dump files allow to greatly speedup the loading process compared
to a client/server based approach.
This is an updated version of D433 (automatically closed as I
pushed it in a separate branch to keep track of the work done
so far), discarding the incremental loading approach through the
use of partial dumps (as numerous tests with real world repositories
end up with errors).