Implement x4 screen resolution

[JNechaevsky]

This should be 1280x800. Still a lot of job to do, but at least reveals how sharp-looking the game can be.

For comparison:

**640x400**  **1280x800** 

[JNechaevsky]

Remaining TODOs for quadres:

• [x] Bunny scrolling code. Half-fixed to interlaced-like horizontal drawing. But where is Y coord meaning/reference in F_DrawPatchCol or how extra *dest should be handled?
• [x] Ammo widget in Heretic. Went off-screen for walking and caught by framebuffer overflow guard.
• [x] Mouse look amplitude is halfed from hires, while shooting trajectories for hitscan/missiles are fine.
• [x] Automap background is broken in Heretic and Hexen.
• [x] Rename extrares to quadres for better understanding?