Fixes report

[Palmer-JC]

I have been trying to use this. I found some fixes. They are small, so just reporting for now. They can be probably updated much faster by some else, then me forking / changing / and PRing.

In GIFEncoder.js:

• line 148, should be sizeSet, not sizeset, causes exception when passing ImageData
• The following lines need to be added to the end of download() to actually make it work:

var click = document.createEvent('MouseEvents');
click.initEvent('click', true, false);
templink.dispatchEvent(click);

[bills-appworks]

I faced problem of download() not work on Mozilla Firefox.
I try to fix and make patch based on following article of Stackoverflow:
https://stackoverflow.com/questions/32225904/programmatical-click-on-a-tag-not-working-in-firefox

My implement is templink element append under document root. It's work fine on Firefox.
But @Palmer-JC 's code seems to more better. I hope to repository taking his code.