Various collision detection

I introduced the circle collision detection for YahooCreativeAward2013, so I looked up a lot of things at that time.

http://marupeke296.com/COL_2D_No7_EllipseVsEllipse.html
http://www.geocities.jp/jtqsw192/FIG/313r/3point_r.htm
http://hvn.to/files/particle/particle7.html
http://marupeke296.com/COL_Basic_No5_WallVector.html
http://cross.hvn.to/?p=650