gifski addition fixed

[soysaucemo]

#962

1. fixed the order of settings (according to gifski's code)
   pub struct GifskiSettings {
   pub width: u32,
   pub height: u32,
   pub quality: u8,
   pub fast: bool,
   pub repeat: i16,
   }
2. Since version 1.4.0 had been pubulished, set it to be default.(dll files'length built by different persons can be different, I got 606720bytes by version 1.4.0 x64)
3. No need to set up lastTimestamp when addframe, it can be auto-calc.
   refer to gifski.h

• Presentation timestamp (PTS) is time in seconds, since start of the file, when this frame is to be displayed.
• For a 20fps video it could be frame_number/20.0. First frame must have PTS=0.
• Frames with duplicate or out-of-order PTS will be skipped.

[Wai-Dung]

@soysaucemo: Maybe this fix has nothing do with x86, because we cannot run it properly on x86 (it doesn't support it at all...)
So you should remove #962 link here to keep your improvements:)

See: ImageOptim/gifski#189

[NickeManarin]

No need to set up lastTimestamp when addframe, it can be auto-calc. refer to gifski.h

No, it needs to be set or the last frame would not have the proper timing.

[NickeManarin]

First frame must have PTS=0.

First frame PTS is used as the last frame PTS. It's a way of setting the correct timestamp.