[FTR] utilised of zope transaction manager
[FTR] utilised of zope transaction manager

- custom drop database
- some helpers for queries, greatest, least, etc.

ThiefMaster/indico,DirkHoffmann/indico,ThiefMaster/indico,mvidalgarcia/indico,indico/indico,mic4ael/indico,indico/indico,mic4ael/indico,mvidalgarcia/indico,DirkHoffmann/indico,mic4ael/indico,indico/indico,OmeGak/indico,DirkHoffmann/indico,DirkHoffmann/indico,pferreir/indico,mvidalgarcia/indico,mic4ael/indico,indico/indico,OmeGak/indico,ThiefMaster/indico,pferreir/indico,pferreir/indico,OmeGak/indico,OmeGak/indico,pferreir/indico,ThiefMaster/indico,mvidalgarcia/indico