yikes, fixed bug introduced straight away, rust2html stopped working when the CrossCrateMap had local nodes, because if it found them it used #n<NodeIndex> references instead of #line_index. So we added ' Some(a) if def_crate>0' to filter out the local case. TODO: we should write out node indices for the local crate aswell?
callgraph generation works
callgraph writes out dotfile