assemble: don't merge yet!

@grayghostvisuals, please review. there is more we can probably do, but I'd love for some feedback first. 

You'll notice big whitespace changes, sorry about that it's unavoidable when switching to templates. However, there are also whitespace changes in non-template-related files. Sorry about those as well, I didn't notice the editorconfig file until now. I'd be happy to reformat as tabs and do another pr if you want. 

let me know what you think in general, and we can go from there.