I think it's user unfriendly to process standard json file with DataFrame

Currently, with DataFrame API, we can't load standard json file directly, maybe we can provide an override method to process this, the logic is as below:
```
val df = spark.sparkContext.wholeTextFiles("data/test.json")
val json_rdd = df.map( x => x.toString.replaceAll("
s+","")).map

{ x => val index = x.indexOf(',') x.substring(index + 1, x.length - 1) }

val json_df = spark.read.json(json_rdd)
```