Add option to disable default persistent TCP connections to ES
add description of new 'http_disable_keepalives' option
Note that an internet connection is required to build
Merge pull request #1088 from validname/validname-es-http_disable_keepalives

Add option to disable default persistent TCP connections to ES
Merge pull request #1097 from markabey/docs-note

Note that an internet connection is required to build
Merge pull request #1096 from markabey/ESjson-fields

Elasticsearch json fields fixes
Update changelog re: PR #1096.
Merge remote-tracking branch 'upstream/dev' into ESjson-fields