log better messages
change Live cache SQL schema
avoid Virtuoso transaction deadlocks on CHECKPOINT
move feeder configuration to property file
Fix according to review: getMessage() may return null, use toString() instead
bugfix provided by @ninniuz
manually merge pull request #95 / fixxes issue #23
bugfix provided by @ninniuz
Merge pull request #142 from jimkont/live_features

Various enhancements for Live