SOLR-4138: CurrencyField fields can now be used in a ValueSources. There is also a new currency(field,[CODE]) function (merge r1452483 and r1452508)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1452527 13f79535-47bb-0310-9956-ffa450edef68