Screen/ES: Fix DrawDots point size lenience mode.

Need slightly different check to make DrawDots work.
Screen/Waffle: Enable EGL vsync control, make X11/EGL default.

If -DPTB_USE_EGL is defined, enable use of eglSwapInterval()
for vsync control and choose X11/EGL as default display
backend instead of X11/GLX. We do so for the ARM/Nexus-7 build.