Update guide/reference/index-modules/analysis/stop-tokenfilter.textile

Filling in important detail regarding file format of stop word config file found below, posted by kimchy 

https://groups.google.com/forum/?fromgroups=#!topic/elasticsearch/0Y6W11xwSdo
Add stretcher ruby client.
add 0.20.3 download
Add Revinate (www.revinate.com) to the users page.
Merge branch 'master' of https://github.com/revinate/elasticsearch.github.com
Added release notes for 0.20.3
Updated links to cookbook in "Deploying Elasticsearch with Chef"
add 0.20.4 download
0.20.4 blog release
forgot to change to 0.20.4 in the text itself