Combining Plugins #18

In the dataflow graphs we've drawn so far, there's quite often linear sections, where a series of nodes each have one input and one output and the intermediate results are not particularly interesting. For example, a file load followed by a regex to extract a column followed immediately by an expression to filter on that column. It'd be nice to be able to show these small operations in combination on the graph rather than as individual nodes.

There'd still have to be some way to tap into intermediate results if/when they became useful, perhaps this should just be a presentational thing where nodes in this kind of relationship are drawn closer together and dragged as one piece, but can be selected/linked individually.