Resolve "Proper drawing of gradients"

Closes #48 (closed)

src/draw.jl

@@ -72,7 +72,9 @@ function _write_dot(io::IO, fst, isyms, osyms)
     for arc in arcs(fst)
         print(io, "  ", stateid[arc.src], " -> ", stateid[arc.dest], " [label=\"")
         print(io, get(isyms, arc.isym, arc.isym), ":", get(osyms, arc.osym, arc.osym))
-        ! isone(arc.weight) ? println(io, "/", arc.weight, "\"];") : println(io, "\"];")
+        if !isone(arc.weight) print(io, "/", arc.weight) end
+        if iszero(arc.weight) print(io, "\" color=\"grey80") end
+        println(io, "\"];")
     end
 
     println(io, "}")