Added INCREASEPRECISION option to caminfo to fix #179. Abstracted the...

Added INCREASEPRECISION option to caminfo to fix #179.  Abstracted the algorithm into ImagePolygon class to accomplish this.  Refactored code to remove memory leaks in the process.  Also added getters for the sinc and linc used to create the polygon in ImagePolygon.  Additionally fixed bug in increase precision algorithm causing sinc and linc to become 0 and enter an infinite loop.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@2875 41f8697f-d340-4b68-9986-7bafba869bb8