Allow ix-sizes to be set with custom input attributes.

[iainhenderson]

All other ix prefixed attributes (ix-src, ix-path, ix-params, and ix-host) can be overridden with custom input attributes for authors concerned about W3C compliance.

However ix-sizes can't seem to be overridden in the same fashion (or at least that isn't documented and I can't spot after a quick scan through the code). This mean my scanning tool is flagging a large number of coding standards issues.

Would it be possible to allow ix-sizes to also be overridden with a custom input attribute, please?

[Hintzmann]

It seems that imgix.js is not being work at anymore.

I needed the exact same thing this morning. So I have created a forge of this git and added support for data-ix-sizes and data-ix-initialized.

You can see the code here: https://github.com/Hintzmann/imgix.js