Eyeserver doesn't start after eye update

[bdevloed]

Issue:

$ docker run --name=eye_server -p 8000:8000 bdevloed/eyeserverERROR: Could not start EyeServer
Possibly the eye command could not be found, or /tmp has no write permission.

Error detail:
 gre ** error(process_error(/usr/local/bin/carl,exit(255)),_4250)

Cause:
Since EYE v18.0131.1211 carl is mandatory

Carl follows Turtle and SPARQL instead of the n3 team submission on several points. This includes no longer defaulting the empty prefix to the local namespace of the file.

This leads to an error at initialization, where the test data contains empty prefixes without a prefix declaration.

I'll send a pull request to fix this