Bug 801: Graph TextRenderer Cleanup Part-4: Text[Render->Region]Util API: Better separation of cached and uncached regions
Bug 801: Graph TextRenderer Cleanup Part-5: *Region API Cleanup (protected impl. part)
Bug 802: Graph TextRenderer Performance Part-3: Reuse 'float[] coordsEx' storage, ease on GC
Bug 801: Graph TextRenderer Cleanup Part-6: Fix TypecastRenderer; Minor Editing

Fix TypecastRenderer:
  - Ensure quad shapes are closed!
  - Revalidate point -> shape interpretation using orig. Typcast code
  - Fix 'midPoint(..)' use float values