Moved CondensedGraphBuilder to javaan library
fixed unit test
extracted functionality for getting source and target vertices of a
given vertex from TraversalDirectedGraph to DirectedGraphUtils
changed method constants to start with class name
First steps for implementing topological sort of multigraph - experimental and buggy
Merge branch 'master' into feature/supportPackageUsageGraph
Revert "First steps for implementing topological sort of multigraph - experimental and buggy"

This reverts commit 8f97fcc3469978e523eda0a6e12c33bfaa9f8c4e.
Introduced unsupported edge factory
- removed ExternalEdgeDirectedGraph, use UnsupportedEdgeFactory in stead
- introduced CyclicDirectedMultigraph, because DirectedMultigraph from
the jgrapht library is not cyclic since version 0.9
fixed verify of mocked visitor, added verifications for method visitedge
added package dependency graph to CallGraph context
added unit test for leave package usage
Refactoring: use cycle detector instead of strong connectivity inspector
for finding dependency cycles. Implemented general method for receiving
dependency cycles from graph.
Implemented package cycle detection
Refactoring: Implemented generalized method for dependency traversal.
implemented traversal of package cycles
Changed CamelCase notation to notation with -
made BaseDependencyGraphCommand more generic so that this class can be
used as base class for package usage commands
implemented commands for package dependeny graph display
added method get types of package