emulator: opengl: use bilinear filtering

This patch changes the filter used to scale the GL window
in the rendering library. Instead of nearest-neighbour, use
bi-linear, which will provide for much more pleasant results
when scaling the emulator UI window, or toggling to full-screen
mode.

Change-Id: If2d9e1300fa4878c25e1221eaedb565b9150431a
1 file changed