code format
pull method filterCandidates(map<node, collection<node>>) to super class awalkercontroller
added RandomWalkWalker
push down method resolveCandidates(Graph,Node) as the actual implementation depends on the concrete Walker implementation
pull up second filterCandidates method
RandomWalkWalkerController
added RANDOM_WALK to SamplingAlgorithmFactory
bug fixing random walk algorithm (ongoing)
Fixing for BUG: writing a network to hdd before calculating the series
Merge branch 'feature/algorithm-randomwalk' into develop