1: add a new util method: CommonUtil.isNotBlank
2:[beecp]rename two methods related with pool lock
getElapsedTimeSinceCreationLock() ---> getPoolLockHoldTime()
interruptThreadsOnCreationLock() ---> interruptOnPoolLock()
3:[beecp] support returning a array of interrupted threads from pool lock
4:[beecp]rename connection eviction predicate class.
SQLExceptionPredication ---> BeeConnectionPredicate
5:[beecp]some optimization on source code
6:[beecp]add toString() method to jdbc proxy objects