Started hacking away at the readme.
Updated the smaller readme sections.

The following are now done:
* Installation & Uninstallation
* Troubleshooting
* Contributing To LOOT
* Translating LOOT
* Credits
* License
* Appendices
Added icons for plugin priorities.
Removed translation section.

Also merged troubleshooting and contributing sections. Translation info
has moved to LOOT's wiki.
Wrote out changelog so far.
Removed pointless note.

Multiple copies of all games edit their shared plugins.txt, just not to
set the load order.
Deleted some images that won't be replaced.
Added CONTRIBUTING.md
Updated README.md

Removed translation section, added snapshot builds section.
Documented archive script features.
Updated settings section of readme.
Updated editor section of readme.

Also added icons to description when talking about them.
CodeMaid code formatting cleanup.
Corrected missing braces.
Implemented thread locking.

Fixes #258. CodeMaid didn't clean up header files, so there are some
formatting changes to app.h here too.
Updated installer YAML settings file.

Replaced debugVerbosity with enableDebugLogging.
Content refresh improvements.

Closes #259.
* On-focus refresh now listens to window event instead of checking for
state change every 0.5s.
* Added setting to enable/disable on-focus refresh.
* Added File menu item to manually refresh content.
* Old settings files get updated when parsed.
* The installer settings file has been updated.
* Swapped the masterlist update icon to a download icon, as it's more
suitable.
Merge remote-tracking branch 'origin/readme-update' into v0.7-alpha
Merge remote-tracking branch 'origin/priority-ui' into v0.7-alpha
Plugin priority icons now only shown in edit mode.

I just made this commit, but GitHub for Windows seems to have ignored it
when merging. >:(