Added optional HTTP authentication against the ElasticSearch HTTP
server. This is needed if you have put a proxy before your ElasticSearch
server that uses HTTPS and Basic Auth to protect access to the
ElasticSearch server.
Merge branch 'dev' of github.com:ghaering/heka into ghaering-dev

Conflicts:
	plugins/elasticsearch/elasticsearch.go
Merge branch 'ghaering-dev' into dev