Hi! 
I just created a compressor/minifier plugin for Kirby as a way to implement my stand-alone PHP Minify project. It supports not only HTML minifier, but also JSON and XML minifier. Inline CSS and JavaScript code inside the HTML will also be minified automatically. It does not depend on PHP dom extension and so it should work fine with broken input as well, as it only parses the string you provide. It is well tested.
Just plug and play! No configuration is required for now. If you want some feature to be configurable, please request the feature by visiting the project page. Thanks!
