[Rdo-list] Middleman -- v4 migration

Quack, I'm looking into migrating the websites Misc built using Middleman to this new major version. I decided to begin with the RDO website which uses many extensions, in order to cover most problems. There's several changes impacting configuration, and I'm not finished yet. Maybe there's also room for cleanup too. So I'm preparing a set of patches and I'd be happy to have your review when ready. On the problems I'm currently looking into and would like some help to be sure the rendered site is as similar as with v3: - source/stylesheets/lib/search.sass hs an @extend for an unexisting h3; I read some doc and it seems it is not possible to extend a tag which is not in the same file or draggued by a @import; so I guess the @extend should be removed or a @import is missing - source/stylesheets/lib/markdown.sass is causing Middleman to use 100%CPU and eat all the memory until the OOM killer triggers; I guess it is related to importing the bootstrap resources but if you have an idea… Regards.