support loaders in 2.0

[ahicks92]

This is followup for #268. Loaders aren't vanilla, so I hereby declare them temporarily broken-ish, and we can deal with it later on.

[ahicks92]

I think this is fine.

In the end it turned out that we need to leave these off the belt analyzer, but you place them and they do their thing. I will revisit if we get reports.