Merge pull request #405 from Amicus/master

return indexes defined on all classes that are descendants of the passed in element class. this makes indexes defined on custom OClasses that extend OrientVertex and OrientEdge accessible.
Stop reading null property values from GraphSON #400
RexsterGraph tests now pass. #403

Changes to the limit api in rexster's handling of vertex query were required as well as the ability to pass multiple values into a has/hasNot property filter.
Changed the limit api for vertex queries in rexster to be skip and take and adjusted RexsterGraph accordingly.
Check edge label for null. #370

Do not allow edge labels to be null.  Enforced with a unit test.
if a class doesn't exist, create it before trying to define an index on it.
Fixed issue on removing of not-updated vertices (when caches are disabled)
Fixed problem against loading of graph elements via remote
look up the super class by name
Merge branch 'master' of github.com:tinkerpop/blueprints into create_class_before_index