Merge pull request #10 from cary-rowen/moreStringsTranslatable

Makes more strings translatable

Update NVDA compatibility to QVDA 2021.3 and fix little update issues

Making the addon ready for NVDA 2021.1

Finally fixes auto-update feature

Changes:

- Fixed a potential crash on exit due to an unterminated thread.
- Little internal updater fixes.
- Do not log each time we check for updates.

Fixes typo

Changes:

- Fixes addon issue with new Google translate.
- New self-updater to make your addon always up to date, hopefully.
- Minor changes

Fixes a clipboard copy bug

Make the addon compatible with NVDA 2019.3

Reflect broken link fix within documentation