1.6.7 released

Use MDIUtilities 1.3
Use jEditor 1.2.21
Emit an error if a package file is invalid
Fix the parsing for mail links
Show an error for not well-formed package XML files
Replace the url by the mail attribute for mails
Fix some cases using the help page in Swing or JavaFX where using the Search function would lead to an exception beginning with Java 9
When the help popup panel is shown in the help component, make sure the focus is on the associated text field
When the help popup panel is shown in the help component, allow to close it by pressing the Escape key
Change the progress bar behavior in the GUI when generating with the default and forked parsers to show the progress percentage
Improve the performance of checking links by adding a new checkHTTPLinksThreaded property and check by default external links in a Thread pool. The function was previously available and effective but was never used
Fix the scrollbars in JavaFX Help format currently overlapping the content
Add a wiki editor
Emit an error if the inputs are empty of any files
Fix the path of errors in the menu which were incorrectly associated with an article