Log Message:
Update to 5.8:

2009.01.01  v.5.8
+ Visual feedback for brightness/contrast/color edits was made faster by
  using the window image instead of the (usually much larger) main image.
  The main image is updated when the changes are committed.
+ Erratic mouse drag in warp function was fixed.
+ Color balance was separated from brightness/whiteness adjustments.
+ Bug fix: last translation in a .po file sometimes got comment appended.
+ Sharpen, blur and noise reduction, when applied within an image area,
  can now use "blend width" to soften the boundaries.
+ Added a modified "top hat" noise reduction method, which is more
  effective for some types of noise.
+ Zoom- returns to normal display at once instead of many steps