Fix location of timelapse.gif put it into series subdirectory

[1fifoto]

Such a little change (a '-' to a '/') to get the resulting animated gif to be located inside of the series subdirectory. For example, previously the file was /home/pi/Desktop/pi-timelapse/series-2018-12-20_18-43-32-timelapse.gif and afterwards it was /home/pi/Desktop/pi-timelapse/series-2018-12-20_18-43-32/timelapse.gif (see the subtle -timelapse.gif to /timelapse.gif). Now all files are housed in their series subdirectory: the captured images, the animated gif and the video mp4 file.