PR for TIFFImageryProvider into TerriaJS!

[staffordsmith83]

Dear Hongfaqiu,

We have got to the point of a PR for TIFFImageryProvider into Terriajs!
I would like to let you know we have had to fork your repo, and make some small changes mostly about importing our custom forked version of cesium. I have put it here: https://github.com/TerriaJS/TIFFImageryProvider/

There is an issue that is blocking our team from accepting the PR, its related to some unnecessary resampling occurring on 4326 COGs - resulting in poor pixel positioning.

I will raise an issue in the repo, thanks so much for the great code, and the demo and everything is very useful too.
Please delete this issue if it is in the wrong place for you.

thanks!
Stafford Smith