* move updateTaskState into try/catch block in case of exception

* fix NPE

* using conf.getInt instead of getString

* for AbstractZKClient, remove the log, for it will print the same log message in createZNodePath.
for AlertDao, correct the spelling.

* duplicate

* refactor getTaskWorkerGroupId

* add friendly log

* update hearbeat thread num = 1

* fix the bug when worker execute task using queue. and remove checking Tenant user anymore in TaskScheduleThread

* 1. move verifyTaskInstanceIsNull after taskInstance
2. keep verifyTenantIsNull/verifyTaskInstanceIsNull clean and readable

* fix the message

* delete before check to avoid KeeperException$NoNodeException

* fix the message

* check processInstance state before delete tenant

* check processInstance state before delete worker group

* refactor

* merge api constants into common constatns

* update the resource perm

* update the dataSource perm

* fix CheckUtils.checkUserParams method

* update AlertGroupService, extends from BaseService, remove duplicate methods

* refactor

* modify method name

* add hasProjectAndPerm method

* using checkProject instead of getResultStatus

* delete checkAuth method, using hasProjectAndPerm instead.

* correct spelling

* add transactional for deleteWorkerGroupById

* add Transactional for deleteProcessInstanceById method

* change sqlSessionTemplate singleton

* change sqlSessionTemplate singleton and reformat code

* fix unsuitable error message

* update shutdownhook methods

* fix worker log bug

* fix api server debug mode bug

* upgrade zk version

* delete this line ,for zkClient.close() will do the whole thing

* fix master server shutdown error

* degrade zk version and add FourLetterWordMain class

* fix PathChildrenCache not close

* add Transactional for createSession method

* add more message for java-doc

* delete App, let spring manage connectionFactory

* add license

* add class Application for test support

* refactor masterServer and workerServer

* add args