Hardware implementation of glyph positioning (bug 5443796)

This implementation adds a drawGeneralText() method to the OpenGL
Renderer, which supports both a global x, y position, an array of
individual glyph positions, and also a length parameter (which enables
drawing of underline and strikethrough. It also adds the method to the
display list (with marshalling and unmarshalling).

With this change, the existing drawText() method is removed entirely, as
it's subsumed by the new method. It's easy enough to revert to the old
functionality if needed by passing in a NULL positions array.

Change-Id: I8c9e6ce4309fd51cc5511db85df99f6de8f4f6f5