Api update

- Removed refresh flag for Flush command (ref elasticsearch/elasticsearch@7cc48c8)
- Removed refresh flag for Optimize command (ref elasticsearch/elasticsearch@df3f681)
- Renamed param "waitForOperations" to "force" for Refresh command (elasticsearch/elasticsearch@8b295b5)
- Added completion and completionFields params for IndicesStats command (ref elasticsearch/elasticsearch@cdddbb7)
- Added support for ClearScroll command (ref elasticsearch/elasticsearch@4864d15)
- Added support for GetTemplates command (ref elasticsearch/elasticsearch@45c0d1d
- Added support for GetFieldMapping command (ref elasticsearch/elasticsearch@8819f91)
- Added support for highlightQuery and highlighterNoMatchSize params in Search cmd (ref elasticsearch/elasticsearch@6b000d8 and elasticsearch/elasticsearch@14a709f)
- Added support for segments stats (ref elasticsearch/elasticsearch@c95c709)
- Added support for cluster stats (ref elasticsearch/elasticsearch@2b6214c)