Setting up code editor

When errors occur in test runs it is possible to click the filenames in the error messages and have the file opened in your favorite editor.

At the moment the default is hard coded to Sublime Text 3, but hopefully this will be improved to be able to detect common editor and allow for quick setups.

Most editors have command line tools to open files, even specify which line to jump to. Look up the documentation for your editor and alter TestUp Preferences to fit.