Change "https://https://" to "https://"

Fix typo in MycroftSkill documentation

Upgrade readthedocs build

* Replace integer values with enum values for clarity
* Simplify exception thrown on incompatible input
* Pythonify (and de-Chanceify) zero-output logic

The queue will store all settingsmeta upload calls and execute them
after pairing can be verified.

Starts settings download after upload has started. When settings meta upload
has started for all skills the skill download process is triggered.

This guarantees that the settingsmeta skill_gid has been populated
properly before skills try to figure out which part of the skills data
belongs to them.

Add docstrings to upload queue

Minor restructuring moving the enqueuing of settingsmeta upload to after
updating the skills manifest.

Skip the queue thread, do upload in series with skill load/reload.

If skill directory doesn't exist in current cache try to fetch a new
copy.

When skills are removed the skills manifest is updated using msm and
then sent to the backend.

- Use reload status directly instead of instance check
- Move manifest posting to start_upload method

Stabilize skill settings download

clean up nice_duration handler

Bugfix/settings sync

$  if [ "$0" == "$BASH_SOURCE" ]; then echo "a"; fi
sh: 1: [: sh: unexpected operator

Fix documentation mistake

…-to-run-unittests

The command to run unittests was wrong documented

…atible-with-sh-and-zsh

Make venv-activate.sh compatible with sh and zsh