title: Incoherent handling of coordinates in basemap addcyclic
body: <p>I have used all <code>mpl_toolkits.basemap</code> functions successfully on several global GCM netcdf datasets. Until I met this grid, with longitudes starting at 0.9375 (instead of 0 as I have always seen) and ending at 359.062.</p>
  
  <p>To prepare a plot, I need to:</p>
  
  <ol>
  <li><p>make the plot continuous with:</p>
  
  <pre><code># input_var is a 2D numpy array
  var_cyclicDUMMY, lons_cyclicDUMMY = addcyclic(input_var, lons)  
  </code></pre>
  
  <p>I thus obtain a 2D array <code>var_cyclicDUMMYwith</code> an extra column (one extra longitude), and a 1D array <code>lons_cyclicDUMMY</code> with one extra element at the end, i.e. one extra longitude, but at 0.9375, instead of the 360 that is needed.
  Indeed in the next step, where I</p></li>
  <li><p>shift the grid, so longitudes go from -180 to 180 instead of 0 to 360, with:</p>
  
  <pre><code>var_cyclic, lons_cyclic = shiftgrid(180., var_cyclicDUMMY, 
                                      lons_cyclicDUMMY, start=False)
  </code></pre>
  
  <p>I get an <code>ValueError: lon0 outside of range of lonsin</code></p></li>
  </ol>
  
  <p>Any suggestions how to get around this with basemap or another solution?</p>