Fiio Snowsky Echo Mini Case with Headphone Wrap

Added a headphone cable wrap (https://www.printables.com/model/34877-earphone-case) to the side of the Fiio Snowsky Echo Mini Case (https://www.printables.com/model/1366785-fiio-snowsky-echo-mini-case-and-pocketbelt-clip). Also added negative space to insert m3 hex nuts on the inside to attach the pocket/belt clip more securely.