Change constructor for IntervalSet back to taking an enumerable
Removed GraphViz property again.
Speeds up interval enumerable by using the node enumerable.
Make FindOverlaps faster by making it iterative instead of recursive.
Removes duplicate method for iterating nodes
Adds contracts suggested by the static analysis.
Replaces the use of C5's Exists with LINQ's Any
Prepares for the removal of nodes
Fixes wrong contract for IInterval<T>.HasEndpoint
Changes QuickGraph to a property to allow it to be used for debugging
Removes unused FindNode method