Remove "stop_threshold"
The setting "stop_threshold" is not used (and doesn't look like it ever was).  Removing
from mycroft.conf.
"upload_skill_manifest": true,
// Directory to look for user skills
"directory": "~/.mycroft/skills",
- // TODO: Old unused kludge, remove from code
- "stop_threshold": 2.0,
// Enable auto update by msm
"auto_update": true,
// blacklisted skills to not load
