[rules-dev] Upgrade JackRabbit from 1.4.5 to 1.5.6

[Jervis Liu]

Hi, is there any objection if I upgrade JackRabbit from version 1.4.5 to 
1.5.6? Compared to 1.4.5, 1.5.6 is the latest major release, has several 
new features, improvements etc. It also has a number of bug fixes for 
concurrency, which might be helpful for the issue I am currently working 
on: https://jira.jboss.org/jira/browse/GUVNOR-346

Cheers,
Jervis