Iss33

Changes
* Update `EnclosedJsonInputFormat` to return false for `isSplitable()`
* Update `UnenclosedJsonRecordReader` to respect `start` and `length` byte offsets defined in the `FileSplit`
 * Added function `findNextRecordStart()` which will find the next record in the document given an arbitrary seek point
* Added test cases for UnenclosedJsonRecordReader