PLINK-268 make Permission a concrete class
fix compiler errors
PLINK-268 differentiate between class and instance permissions
PLINK-268 updated methods in reference docs
PLINK-286 foundational infrastructure for privilege inheritance
PLINK-268 configuration support for registered identity types and relationship types
PLINK-268 initialize privilege chain query with configured relationship types
ÇMerge branch 'master' of github.com:picketlink/picketlink