Remove round-trip to master upon "load" call.
Move load/loadBefore/loadSerial/loadEx from app.py to Storage.py.
This is required to get rid of master node round-trip upon each "load"
call.
Get rid of no-op-ish "sync" implementation.
Separate "undoing transaction ID" from "undoing transaction database
snapshot" when undoing.

git-svn-id: https://svn.erp5.org/repos/neo/trunk@2532 71dcc9de-d417-0410-9af5-da40c76e7ee4