Increase camera angle to 60 degrees

Increase camera angle to 60 degrees

Using the 30 degree viewing angle looks reasonable realistic,
but is difficult to use since it requires much more panning.

Derivation of FOV_DIST for a 1600x1200 monitor
with a vertical viewing angle of 60 degrees:

        ---  +.
         |   | '-.     angle
  height |   |    '-./
  (px)   |   |      /'-.
         |   +------|---+ (o) eye
         |   |      \ .-'
         |   |     .-'
         |   |  .-'
        ---  +-'

             |----------|
               FOV_DIST (px)

  height   = 1200 px
  angle    =   60 deg
  fov_dist = cot(angle/2)*(height/2) = ~1039.23

Derivation of angle for window of a given height:

  angle    = atan((height/2)/FOV_DIST)*2