Expose getMemoryUsage as player method to python.

Deprecating avg.getMemoryUsage as of 1.9.0
Adjust removal comment
Expose pointInPolygon as avg.Point2D.isInPolygon

Finish item on #291
Depcrecate avg.pointInPolygon
Merge pull request #507 from libavg/features/#291

Features/#291: Point2D::isInPolygon and Player::getMemoryUsage