Upgrade project for gltf-pipeline

[lilleyse]

A made a bunch of structural changes so that more functionality is handled by the gltf-pipeline. The diff is a little crazy mostly due to indenting now that some callback stages are removed.

Changes:

• Removed the shader technique cmdline option and modelMaterialCommon.js. This is now handled in the gltf-pipeline.
• Removed auto-generating normals if they are missing. Instead I added this to the gltf-pipeline roadmap
• Removed util files and instead am including Cesium
• Added gulp, jsHint tasks, .idea, .npmignore, and index.js
• Added convert.js, which is the starting point for code that wants to use obj2gltf as a library

TODO

• OBE - linking to the git repo for now. This won't be ready to merge until the gltf-pipeline is published to npm.

[pjcozzi]

Removed auto-generating normals if they are missing. Instead I added this to the gltf-pipeline roadmap

Should we do this soon? Is this often needed for OBJ models?

[pjcozzi]

@lasalvavida can you please test this?

[pjcozzi]

Here's a few test models: https://github.com/SaschaWillems/Vulkan/tree/master/models

If any didn't work before this PR; it is OK if they don't work now; we just don't want to break ones that previously worked.

[lasalvavida]

@pjcozzi There are two obj models in that repo, chinesedragon and hammardillo and both convert correctly with these changes.

@lilleyse I would advise perhaps just adding gltf-pipeline as a git dependency for now if that's possible so these changes can get merged and then updating once gltf-pipeline is in npm.

[lilleyse]

Updated

[pjcozzi]

Thanks for the review, @lasalvavida. Please merge when ready.

[lilleyse]

This is also ready.

[pjcozzi]

@lasalvavida you should have commit access to this now to review and merge when ready.