https://github.com/nuvolabase/orientdb/pull/1406

Fix https://github.com/nuvolabase/orientdb/pull/1406
Merge branch 'master' of git://github.com/nuvolabase/orientdb
https://github.com/nuvolabase/orientdb/issues/1226
fix https://github.com/nuvolabase/orientdb/issues/1226
Fixed problem on SUM when the sum of 2 integer breaks the INTEGER limit. The same for short types
Fixed bug on union and management of collection/arrays using the dot notation
SQL: fixed UNION function to recognize collection of collections
Merge pull request #1435 from scenari/master

 Fix issue #1431 (Tx and NoTx used concurrently)
Merge branch 'master' of git://github.com/nuvolabase/orientdb
Merge pull request #1430 from henryzhao81/master

https://github.com/nuvolabase/orientdb/pull/1406
Revert "Fix issue #1431 (Tx and NoTx used concurrently)"

This reverts commit f1c28586d4b714ecb9fbc6ac04908252aa54ccfc.