OAK-50: user mgt

- ensure backward compatible behavior of querybuilder#setLimit which used to allow -1 to indicate that the max number of result should not be limited.
- tests asserting the same results with maxCount being set to Long.MAX_VALUE and -1 both with and without limiting the scope of the result to a given group (-> different test executing in the code).

- use constants

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1512281 13f79535-47bb-0310-9956-ffa450edef68