Merge pull request #113 from iKeirNez/dev

Allow a custom ExecutorService to be set for each pool
Synchronize HikariCP-java6 code with HikariCP for pull request #113
Updated changes file
Fix #115 do not call addBagItem() from housekeeping thread if minimumIdle is 0.
Fix #115 do not call addBagItem() from housekeeping thread if minimumIdle is 0.
Fix #116 recursively call isWrapperFor() and unwrap() per spec
Update changes log.
Use internal flag to determine whether to persist generated proxy classes.
Add version to submodules.
Fix indentation.
Fix race condition that would lead to un-acquired connection and timeout.
pom cleanup
pom cleanup
pom.xml experimentation.
[maven-release-plugin] prepare release HikariCP-2.0.0
[maven-release-plugin] prepare for next development iteration
Fix #125 add java version check around ScheduledThreadPoolExecutor.setRemoveOnCancelPolicy() for Java 6.
Sync Java 6/7 and Java 8 versions
[maven-release-plugin] prepare release HikariCP-2.0.1
[maven-release-plugin] prepare for next development iteration