Tab indent support and bug fixes

Long time in coming but a new release is out with some much needed bug fixes, updated documentation and a few additional features:

Bug fixes

• Fixed issue where clicking the ignition switch buttons twice in quick succession would break the editor - thanks to @Hoiy for the spot and report.
• Fixed issue where EditorApp.revertToSnapshot (used when calling undo/redo) would corrupt key lastModified timestamps against the root element and region elements preventing the correct changes being reported on save - thanks very much to @ChrisKanger for spotting and reporting this.

Features

• We now have a Danish translation thanks very much to @Reached.
• Tab indentation in PreText elements is now a feature - I love this one since most of the time when I'm using CT I'm writing technical documentation with examples, suggested a long time ago by @bfintal (thank you :)) took a little longer than planned to implement.
• It's now easy to capture events for when tools are applied, you can now listen tool-apply and tool-applied events against the EditorApp. The event includes details of the tool class applied, the element it's applied to and if applicable the content selection.