Adding Petersen graph and digraph
Adding test for CompleteGraph methods

Test:
- K0GraphTest -> Test creation of 0 complete graph
- K5GraphTest -> Test creation of 5 complete graph
Adding Named class

Moving petersen graph related methods to this class
Fixing bug in petersen graph creation

Adding and refactoring test:
- PetersenGraphTest (added)
- PetersenDiGraphTest (added)
- K0DiGraphTest (added)
Adding bipartite graph (digraph) and tests

Methods:
- CompleteBipartiteGraph -> SGraph
- CompleteBipartiteGraph<> -> TGraph (generic)
- CompleteBipartiteDiGraph -> SDiGraph
- CompleteBipartiteDiGraph<> -> TGraph (generic)

Tests:
- K00GraphTest
- K55GraphTest
- K00DiGraphTest
- K55DiGraphTest
Adding Star graph and related tests
Reordering Assert.AreEquals parameters to match expect and receive signature
Merge branch 'models' into dev