Intersector.overlapConvexPolygon directionality

Fixed the issue with Intersector.overlapConvexPolygon not honoring directionality with respect to moving p1 out of p2 as per issue described in Issue #1898.
Update Intersector.java

Removed unneeded division and multiplication (As the values are scalar scaling of the values and do not change the outcome of the subsequent ternary operation.)
Update Intersector.java

Fixed the method for determining the direction of the overlap.
Update Intersector.java

Superfluous tab in method declaration.
Update Intersector.java

Fixing description of changed methods.
Merge pull request #1900 from UprightPath/patch-1

Intersector.overlapConvexPolygon directionality