Use smallgraph instead of graphfamous

The graphfamous function of this package was deprecated a while ago and
the karate was moved to LightGraphs.

Author: simonschoelly

README.md

@@ -25,7 +25,8 @@ using GraphPlot
 # Usage
 ## karate network
 ```julia
-g = graphfamous("karate")
+using LightGraphs: smallgraph
+g = smallgraph(:karate)
 gplot(g)
 
 ```