Alexander Meindl

I fixed user settings for Redmine => 3, integrated the latest hightligh.js 9.12.0 and did some code cleanups. Would be nice, if you merge my changes. cu alex

To get more compatibility with other plugins, it would be great to use [redmine_plugin_kit](https://github.com/AlphaNodes/redmine_plugin_kit) Gem instead of [redmine_base_deface](https://github.com/jbbarth/redmine_base_deface) plugin. This would also be easier for users, because they do not...

mini_magick removed deprecated Image#mime_type with version 5, see https://github.com/minimagick/minimagick/releases/tag/v5.0.0 With mini_magick v4.x I got the following warning with rbpdf: ```ruby pdf.image image_path [MiniMagick] MiniMagick::Image#mime_type has been deprecated, because it wasn't...