title: Plotting directed multigraphs in R
body: <p>I've never used any graph plotting package in R, I'm  familiar with basic plotting commands and with <code>ggplot2</code> package. What I've found (but not tried out yet) are <code>Rgraphviz</code>, <code>network</code> and <code>igraph</code> packages. So I'd like to ask you, which package has simplest learning curve and satisfies following requirements:</p>
  
  <ul>
  <li>Has simple layout engines (spring layout, random, ...)</li>
  <li>Tries to draw multiple edges between two vertices so that they would not overlap. As a bonus it would be nice to being able to adjust this.</li>
  <li>Can draw loops.</li>
  <li>Vertex and edge labels, vertex and edge size and color are adjustable.</li>
  <li>(No need for any of the graph algorithms like link analysis, shortest path, max flow etc, but nice, if present)</li>
  </ul>