Generate the images with the correct size

[hugozap]

The images generated by the original script have the same size as the document.
This pull request fixes that so every image has the same size as its layer.

It selects the current visible layer and trims the document before saving the layer.
At the end, the original document canvas size is restored.

[antipalindrome]

I know I'm longer overdue on this, but I tested it tonight and this kind of completely destroyed my Photoshop file (it exported just fine, but after exportation all my layers are blank and the document in general is just messed out.)

So while the output is great and it doesn't slow the script down that much I really like the additions but the destructive nature of this script requires me to not merge your request.

[hugozap]

Hi, yeah, i noticed that some days after sending the request
However i have already fixed it by using a temporal document to copy the layers , trimming and saving the image so the original document is never touched (not even to hide layers).

I'll try to submit a new request with those improvements, even if not merged it could still be useful for somebody.

[antipalindrome]

Great!
Well I'll be sitting down soon with another collaborator and we're going to organized and improve my script and hopefully work in some new features. If I have your updated script perhaps we can take some of your improvements and work them in as well.

Thanks.

[skjorn]

This is basically an implementation of #5. I'm closing it as we'll need to implement it slightly differently, although the idea is clear.