SVK::Editor::Patch - An editor to serialize editor calls.
$patch = SVK::Editor::Patch->new...
# feed things to $patch
$patch->drive ($editor);
"SVK::Editor::Patch" serializes incoming
editor calls in a tree structure.
"$editor-"{edit_tree}> is an array
indexed by the baton id of directories. The value of each entry is an array of
editor calls that have baton id as parent directory. Each entry of editor
calls is an array with the first element being the child baton id (if any),
and then the method name and its arguments.