Bump Hadoop dependency to latest stable

This commit bumps the Hadoop dependency to the latest stable Apache
Hadoop release (1.2.1)
Add .settings to ignore file
Ignore pig run logs
Add ToString() method to SerializedGraphElement

Adds a ToString() implementation to SerializedGraphElement which allows
the generated graph to be usefully dumped for debugging with the Pig
DUMP built-in.
Work towards having proper Property Graph and RDF Mappings

This commit adds infrastructure classes which help implement a much more
flexible declarative approach to property graph and RDF mappings.  These
implementations are not yet complete or tested.
Finish most of the Mapping infrastructure classes

This commit finishes off most of the remainder of the Mapping
infrastructure classes
Finish initial implementation of mapping classes
Make toString() of Vertex and PropertyMap more readable
Start implementing property graph mapping

This commit starts to actually implement the revised property graph
mapping strategy.  Currently only vertex mappings are implemented with
edge mappings to follow in a subsequent commit.
Make Edge.toString() more readable
Finish revised Property Graph mapping implementation

This commit finishes off the new approach to property graph mapping
providing the implementation for edge generation.
Start implementing proper RDF mapping

This commit adds partial implementation of the new RDF mapping
technique.  Currently only mapping of edges into RDF is supported with
mapping of vertices (which is more complex anyway) to come in a later
commit.
Complete RDF Mapping implementation

This commits completes the implementation of Property Graph -> RDF
triple mapping adding the missing vertex mapping logic
Fix a minor bug in RDF mapping

This commit fixes a minor bug in the RDF mapping and one in the
associated example Pig script
Fix tests for CreatePropGraphElements UDF

This commit fixes the CreatePropGraphElements UDF unit tests to account
for the change in how mappings are defined and implemented.  It also
adds a broader range of tests and updates the UDF to work with both
direct and nested tuples improving its portability
More unit tests for CreatePropGraphElements UDF

This commit adds more unit tests to the CreatePropGraphElements UDF to
exercise it further.  It also adds a useful toMap() method to the
mapping classes to allow converting instances of them back into Map form
which is useful when constructing unit tests.
Fix most of the remaining broken tests

This commit fixes up most of the remaining broken tests other than those
for the RDF UDF where there has been heavy refactoring
Comply with Cray Legal requirements

This commit adds the necessary copyright statements and license headers
to fully comply with Cray legal requirements prior to being able to make
our GraphBuilder fork public
Convert README into proper Markdown
Further update README