Made PropertyGraphSail configurable such that edges may either be viewed as first-class objects (with one edge per id, type, label, head, and tail) or as single statements
Added a saveRDF method to SaiGraph, to complement loadRDF
added a test to ensure proper behavior around updating a vertex's property.
Minor: removed all the compilation warnings
Merge branch 'master' of git://github.com/tinkerpop/blueprints