Rated 5 out of 5 stars

how can one disable the about:new tab crap? why is firefox going so downhill with all those unnecessary changes? (thanks alejandro!)

This review is for a previous version of the add-on (1.0.1). 

Well...you simply can click the square icon in the top right of the page. Customize about:newtab will still work.
Also, you can use the add-on "Custom new tab" to change it: https://addons.mozilla.org/es-ES/firefox/addon/custom-new-tab/