[DOCS] Fixed some bad UTF8
Use BytesReference to write to translog files
Instead of using byte arrays, pass the BytesReference to the actual translog file, and use the new copyTo(channel) method to write. This will improve by not potentially having to convert the data to a byte array
closes #5463
Significant_terms agg only creates term frequency cache when necessary and uses new TermsEnum wrapper to cache frequencies. Long and String-based aggs no longer need to pass an IndexReader as parameter when looking up frequencies of terms.
Closes #5459
Add exceptions to `GeoPointFieldMapper` when parsing `geo_point` object

* moved `geo_point` parsing to GeoUtils
* cleaned up `gzipped.json` for bulktest
* merged `GeoPointFieldMapper` and `GeoPoint` parsing methods

Closes #5390