bugfix: update size field in MemPool
add some utility methods to SpotCollection.
fix leftovers from renaming AbstractSpot to AbstractVertex
add javadoc
add javadoc
Edge and Vertex interfaces implemented by AbstractEdge and AbstractVertex
bugfix: AbstractIdVertex.SIZE_IN_BYTES was wrong
javadoc
missed in renaming: tmpSpot to tmpVertex
bugfix: OFFSETS in Spot were calculated wrong
added Graph interface and default implementation
SpotCollection.getGraph returns contents as a Graph< Spot, Edge >.