PLINK-515 : AbstractSPFormAuthenticator has NPE if principal is null
Merge pull request #87 from anilsaldhana/master

PLINK-515 : AbstractSPFormAuthenticator has NPE if principal is null
Merge pull request #88 from pedroigor/master

[PLINK-516] - PicketLink AbstractIDPValve does not trigger the next valve in the pipeline.