Add import graph (agi) + new ag? help #10132
Added the import graph, which is basically a cross-references graph to all the imports.
Also, since all graph types are mostly done, I decided that it was time to update ag? help.
I also changed
Fixed one or two things from my last pr (in particular, there was a compiler warning about unused variables).
After this pr what's left to do is addressing some issues with argument handling (the infamous agj @ 0) and adding capital letters for global graphs (which shouldn't be difficult) and then I think I'll have finished with ag*