Current time of day (warp) fixes:

Current time of day (warp) fixes:

- sim-speed-up (a/A keys) offsets warp correctly. This means at 4x speed
  up the warp will increase by 3 seconds for one elapsed real second.
  In practice this means simulation elements timed using sim ‘current time’
  will be correctly synchronised with those using simulated elapsed time.

  (AI traffic being a prime example of this)

- warp-delta (t/T keys) is independent of frame rate, and works when
  paused. The warp-delta values in the keybindings / GUI dialog
  will need to be updated since warp-delta in now seconds-per-second,
  as opposed to seconds-per-frame.