SP1 hotend

THIS IS A WORK IN PROGRESS

Many hotends seem designed to jam. I'm working on this design to hopefully reduce one source of jamming - the number of physical connections the filament must meet. Most of my jams seem to take place at the nozzle/aluminum block or at the "neck"/aluminum block meeting points, so making the heating block surround the hotend rather than relying on the soft aluminum as part of the mechanical structure itself. I still need to put in real values for the filament intake h