Streaming DICOM

This release comes with a significant change in the technology used to ingest, parse, modify and transfer DICOM data. It is built on the AKKA Stream implementation of the Reactive Streams protocol, which means that DICOM data never fully buffered in memory. Instead, minimal fragments are read, processed and passed on to storage, another instance, or the client. This makes the application more stable and predictable in terms of system resources usage. Streams use back-pressure to communicate between network nodes the rate at which data should be produced and consumed. This avoids build-up of buffered data at any node and makes network utilization more even. These changes makes slicebox more stable and better performing under load.