DetectedLanguageWriter is now a JAX-RS provider. In addition the produced JSON is not compatible to the Specification by [STANBOL-894](https://issues.apache.org/jira/browse/STANBOL-894)

Added @Consumes("text/plain") annotation to the BlobReader to confirm to the service specification of [STANBOL-892](https://issues.apache.org/jira/browse/STANBOL-892) requesting that requests MUST use the "text/plain" Content-Type