fix OpenGL resource leak

Change-Id: I56d00381dc023273c406a134c0828bda89d4d6b2
last fix for chart area size and positioning

It WORKS!!!!!!! The chart looks good and there are now only minor
positioning issues. Issues that I'm aware of:

* legend text is not positioned correctly
* text seems to be positioned a bit too far to the right
* bubble positions are incorrect

Change-Id: Ib81cae13624c8119216f0bedea58b5838fcdc80c