Create Polygons.java
Create NchooseR.java
Merge pull request #6 from NsValleyMan/patch-2

Merge Polygons.java, NchooseR.java.
Move Polygons.java into the Geometry module.
Use java.awt.geom.Point2D in Polygons.java.
Add unit test for Polygons.java.
Relocate and rename combinatorics functions.
Faster, long-safe factorial method and tests.
Rename and reformat combinatorial functions.
Merge pull request #4 from polaris8920/master

Created an adjacency list version of a graph.
Fix inappropriate use of size() in factorial(int).
Points must be sorted for polygonal area.
Add side of line of point.