Add scheduling, machine info, caching strategies and devices (#9)

Reviewed-on: Rubydragon/MetagraphOptimization.jl#9
Co-authored-by: Anton Reinhard <anton.reinhard@proton.me>
Co-committed-by: Anton Reinhard <anton.reinhard@proton.me>

src/diff/print.jl

@@ -6,6 +6,6 @@ Pretty-print a [`Diff`](@ref). Called via print, println and co.
 function show(io::IO, diff::Diff)
     print(io, "Nodes: ")
     print(io, length(diff.addedNodes) + length(diff.removedNodes))
-    print(io, " Edges: ")
+    print(io, ", Edges: ")
     return print(io, length(diff.addedEdges) + length(diff.removedEdges))
 end