modified skeleton parsing logic to allow for alphanumeric skeleton ids, cleanup formatting

src/Bones/skeleton.ts

@@ -770,7 +770,7 @@ export class Skeleton implements IAnimatable {
 
         skeleton.needInitialSkinMatrix = parsedSkeleton.needInitialSkinMatrix;
 
-        if (parsedSkeleton.overrideMeshId){
+        if (parsedSkeleton.overrideMeshId) {
             skeleton._hasWaitingData = true;
             skeleton._waitingOverrideMeshId = parsedSkeleton.overrideMeshId;
         }

src/Meshes/mesh.ts

@@ -3455,7 +3455,7 @@ export class Mesh extends AbstractMesh implements IGetSetVerticesData {
         }
 
         // Skeleton
-        if (parsedMesh.skeletonId) {
+        if (parsedMesh.skeletonId !== undefined ) {
             mesh.skeleton = scene.getLastSkeletonByID(parsedMesh.skeletonId);
             if (parsedMesh.numBoneInfluencers) {
                 mesh.numBoneInfluencers = parsedMesh.numBoneInfluencers;