Fixed link to contribution guide in README

Closes #402
Add more info about the minimum_should_match syntax. Also rename
"minimum_match" and "minimum_number_should_match" references to
"minimum_should_match"

From:
http://lucene.apache.org/solr/4_3_1/solr-core/org/apache/solr/util/doc-files/min-should-match.html
Edited links to min-should-match

Closes #454
Marked JMX as removed

Closes #408
Update index.textile

An update For a NodeJS client for elastic search.
Merge pull request #455 from picatchumm/patch-1

Update index.textile
added link to hazelcast river
Merge pull request #456 from sksamuel/patch-4

added link to hazelcast river
Fixed JSON parse error in histogram facet script example.
Merge pull request #457 from robhudson/histo-parse-fix

Fixed JSON parse error in histogram facet script example.
Add note that index aliases add/remove is atomic. Closes #438
there isn't any memory caching in es anymore
Update plugin documentation relative to https://github.com/elasticsearch/elasticsearch/issues/3112 and add old options for ES prior to 0.90.2