First step of weight refactoring: generate them through GDS

Following: fixing red lights in metrics
WeightedGraph and NullWeight no longer needed - GDS transparently creates weighted elements if needed

This is directly put into the according test cases
Refactored outputting of Weights
Bugfix: assume a minimal initial size of 1
GeneratorsTest should use all edge and node types again
Reflect recent changes in the last test cases
Remove un-needed checks
Changed metrics to work with the new metrics structure
Make travis aware of a moved build.xml, and exclude one jar from build
Tiny bugfix for the test cases
Push some stuff from (Un)Directed to the upper class -- metrics might need additional changes, esp. in terms of checking for more duplicated code
New getter for edges by its attached nodes
Straight forward: remove old occurence of getting an edge by a dummy edge
Some fixes for the test cases
moves keywords for io from config to static fields
moves random edge weight batch generators to rand pkg
shortens update keywords (e.g., NODE_ADDITION => NA)
refactors dna.graph.weightsNew to weights