Revert "DataFrame.toJSON should return an RDD and not do a collect"
Revert "DataFrame.toJSON should return an RDD and not do a collect"

This reverts commit 477f72766dc5e5e0812e12af7c4a9fc874bb4d6b.

EclairJS/eclairjs-nashorn,doronrosenberg/eclairjs,doronrosenberg/eclairjs,doronrosenberg/eclairjs,EclairJS/eclairjs,EclairJS/eclairjs-nashorn,conker84/eclairjs-nashorn,doronrosenberg/eclairjs,EclairJS/eclairjs,EclairJS/eclairjs,conker84/eclairjs-nashorn,doronrosenberg/eclairjs,EclairJS/eclairjs,conker84/eclairjs-nashorn,EclairJS/eclairjs-nashorn,EclairJS/eclairjs-nashorn,EclairJS/eclairjs