ACT-2112 JtaTransactionInterceptor hides exception

It is possible that JtaTransactionInterceptor swallows original
exceptions, when an exception is thrown on rollback.
ACT-2112 JtaTransactionInterceptor hides exception

When exception occurs on rollback, the original causing exception is lost.
FIX: log.error the original exception upon throwing the new one.
fix http://jira.codehaus.org/browse/ACT-2123, add sequence label
change tab to space
replace deprecated method
Added support for compensation event definitions by using 'org/activiti/icons/compensate-throw.png' and 'org/activiti/icons/compensate.png'
Register rollback listener before executing the job
Merge branch 'fix/jobexec_rollback' of https://github.com/dmandalidis/Activiti
Merge pull request 361
Manually merge of pull request 433
Adding getters and setters to ProcessDiagramGenerator to cater for http://forums.activiti.org/content/new-task-icons-doesnt-appear
Manual merge for pull request 389
Merge branch 'master' of https://github.com/Activiti/Activiti
Merge branch 'ACT-2123' of https://github.com/xuhuisheng/Activiti
Change in sequence flow name logic