Update imguralbum.py

[vinieich]

I changed imageIDs from list to set, so it doesn't return duplicate imgs ever. This is my first collaboration, sorry if this is not the way and please contact me.

[zuik]

Ditto on this as it would solve issue #37

[szero]

This was already done here #26

[Kagami]

@Szero your version gives the following error:

$ ~/imguralbum.py http://imgur.com/a/uOOju           
Traceback (most recent call last):
  File "/home/user/imguralbum.py", line 207, in <module>
    downloader = ImgurAlbumDownloader(args[1])
  File "/home/user/imguralbum.py", line 96, in __init__
    for i in self.imageIDs:
AttributeError: 'ImgurAlbumDownloader' object has no attribute 'imageIDs'

This one works, so :+1:

[szero]

@Kagami Thanks, I updated it so it works like it should now.

[vinieich]

Closing to prevent duplication as @Szero too has a working version.