[extensions] KHR_draco_mesh_compression (decode only)

[donmccurdy]

1/2 for #9.

Remaining:

• Tests
• Documentation
• Improve I/O roundtrip story

[donmccurdy]

Including the Draco library seems to mess with my stack traces in node.js. This error shouldn't be related to draco at all, Draco wasn't involved at the code that failed. 😕

/Users/donmccurdy/Projects/glTF-Transform/node_modules/draco3dgltf/draco_decoder_gltf_nodejs.js:9
var Module=typeof DracoDecoderModule!=="undefined"?DracoDecoderModule:{};var isRuntimeInitialized=false;var isModuleParsed=false;Module["onRuntimeInitialized"]=function(){isRuntimeInitialized=true;if(isModuleParsed){if(typeof Module["onModuleLoaded"]==="function"){Module["onModuleLoaded"](Module)}}};Module["onModuleParsed"]=function(){isModuleParsed=true;if(isRuntimeInitialized){if(typeof Module["onModuleLoaded"]==="function"){Module["onModuleLoaded"](Module)}}};function isVersionSupported(versionString){if(typeof versionString!=="string")return false;const version=versionString.split(".");if(version.length<2||version.length>3)return false;if(version[0]==1&&version[1]>=0&&version[1]<=3)return true;if(version[0]!=0||version[1]>10)return false;return true}Module["isVersionSupported"]=isVersionSupported;var moduleOverrides={};var key;for(key in Module){if(Module.hasOwnProperty(key)){moduleOverrides[key]=Module[key

Error: abort(g: GLB must have exactly 1 buffer.). Build with -s ASSERTIONS=1 for more info.
    at process.abort (/Users/donmccurdy/Projects/glTF-Transform/node_modules/draco3dgltf/draco_decoder_gltf_nodejs.js:35:7672)
    at process.emit (events.js:214:15)
    at processPromiseRejections (internal/process/promises.js:201:33)
    at processTicksAndRejections (internal/process/task_queues.js:86:32)

Fixed with a custom build of draco3dgltf.