add license and repo
Support additional types of filter scripts

Add the "scriptType" setting to allow the user to
use another type of script. Defaults to "js" if 
not specified.
Update README.md
Merge pull request #13 from mullr/filter-script-type

Filter script type
Fix typo
Merge pull request #18 from pangratz/patch-1

Fix typo
Move to Elasticsearch 0.21.0.Beta1
Due to refactoring in 0.21.x we have to update this plugin
Closes #23.