fix for STANBOL-898: The StreamSource does no longer close the parsed InputStream. In addition it returns an non-closeable InputStream on calls to #getStream() to ensure that also Users that obtain an reference to the parsed stream are not able to close it. The Documentation of the create** methods in the ContentItemFactory where also updated as requested by the issue; Minor: changed references to the deprecated junit.framework.Assert class to org.junit.Assert

git-svn-id: https://svn.apache.org/repos/asf/stanbol/trunk@1436798 13f79535-47bb-0310-9956-ffa450edef68