Maven integration

Converted project to Maven structure, setup Maven Central release.

v1.1

API improvements.

• Added AbortBeforeIfModule
• doConsiderEdgeForRelaxiation for DijkstraModules exposes TentativeDistance as additional argument
• SimpleGraph and SimpleEdge are not final anymore
• Path can now be iterated reversely via reverseIterator()
• Added 2 shortestPathReachable methods which return a PathTree for more complex path retrieval

v1.0

Initial release version.

Maglev is feature-complete.