This is Compensation 6.0.x

[Aug 1, 2013, 12:40] This is the final pull request that implements compensation the right way. 

For info about compensation, see my now (fairly extensive) notes about it here: 

https://github.com/mrietveld/jbpm/wiki/Compensation

What's *not* supported, and won't get in in 6.0 is the following: 
- "persisted" compensation (think tasks/safe points in a compensation handler)
- multi-instance + compensation

However, this pull request lays a good basis for being able to implement these things later.