hotfix

1.support back connection connects timeout
2.only MySQL type datasources can create tables automatically
3.R/W support update/delete join
4.remove mapdb
5.add SQLCreateFunctionHandler/SQLDropFunctionHandler
6.fix prepare statement execute wrong long value
7.fix alter table statement #558
8.service unavailable due to repair exception 864b864
9.support heidisql
10.fix PartitionByMonth,PartitionByHotDate
11.allow nested transactions