Hotfix for a Startup Crash

Quite a few of you, excited to see the launch of 2.2.0, saw the app crash instead of displaying to you all the neat improvements we have stacked into the update. The cause* was luckily quickly found and, with this update, we fix it. Additionally, there are a few minor additional changes, as usual, because the train of progress never stops 🚂🚃🚃🚃.

* For those interested: Somehow we managed to sneak an infinite loop into the app, one of the most rookie mistakes one can possibly make.

Changelog

GUI and Functionality

• Fixed an error that would under certain circumstances crash the application on
  start
• Fix an error that would make some actions unusable if a faulty translation was
  provided
• Fixed an issue where sometimes moving the cursor to the beginning of a list
  item would misbehave
• Zettlr now detects if a directory is a git repository and displays this
  information in the directory properties
• Zettlr can now also preview emphasis such as italic or bold text
• Using an absolute path as the default image location will ensure that pasted
  images will be inserted using absolute paths as well.
• Sometimes, something goes wrong when you start the application; now you will
  receive an informative message box if that happens, so that reporting problems
  will be easier

Under the Hood

• Other files are now stored in the children array; the attachments array is
  now gone for good
• Removed old remnants of the experimental WYSIWYG mode, since Zettlr now offers
  this via the ensemble of all rendering plugins in the main editor
• Incorporate the logic to disambiguate ID and filename links into
  FSAL::findExact()
• Improve findObject utility function
• Resolve outbound links directly in the link provider