Added structure that contains the terms needed in influence calculations for both source and doublet panels.  Terms found in Katz and Plotkin page 246 and based on geometry of panel and the point of interest.
Modified panel geometry test to confirm ability to handle both triangle and quadrilateral geometries
Changed the way points are fed to convex hull.  Now points are in a Nx3 matrix rather than a vector of points.
Added ability to handle quadrilateral panels in addition to triangles
Made changes in convex hull test to correspond with modified way of passing points to the constructor.