File overwritting while multiple-processing codecs.

[kny5]

While using Nimble, CADOrchestrator. Handling multiple request on parallel is not currently possible, as the files are fixed named under /tmp in linux for example. "temp_stl.stl", "temp_dxf.dxf". Multiple processing would try to write/read the same files, creating bottlenecks and other unwanted overwriting conditions.

[jmwright]

Will be resolved by #40