Add testcase for issue #72 : performance of LayerNodeIndex:add()
issue #72 testcase: add linearity statistic (time per step per node in index)
Merge branch 'issue-72' of https://github.com/jonathanwin/neo4j-spatial
Updated copyright to 2013
Commented out performance test for now until we can fix performance bug in https://github.com/neo4j/spatial/issues/72