HBase/Accumulo Input and Output formats

Four abstract classes that wrap their respective delegate input/output formats for
easy hooks into vertex input format subclasses. I've included some sample programs that show two very simple graph
algorithms. I have a graph generator that builds out a very simple directed structure, starting with a few 'root' nodes.

Root nodes are defined as nodes which are not listed as a child anywhere in the graph.

Algorithm 1) AccumuloRootMarker.java --> Accumulo as read/write source. Every vertex starts thinking it's a root. At superstep 0, send a message down to each
child as a non-root notification. After superstep 1, only root nodes will have never been messaged.

Algorithm 2) TableRootMarker --> HBase as read/write source. Expands on A1 by bundling the notification logic followed by root node propagation. Once we've marked the appropriate nodes as roots, tell every child which roots it can be traced back to via one or more spanning trees. This will take N + 2 supersteps where N is the maximum number of hops from any root to any leaf, plus 2 supersteps for the initial root flagging.

I've included all relevant code plus DistributedCacheHelper.java for recursive cache file and archive searches. It is more hadoop centric than giraph, but these jobs use it so I figured why not commit here.

These have been tested through local JobRunner, pseudo-distributed on the aforementioned hardware, and full distributed on EC2. More details in the comments.