title: python RGB colormap colors incorrect
body: <p>I have an array of RGB colors from 0 - 255 along with the numerical boundaries that should limit the color ranges:</p>
  <pre><code>        colormap = [[149,148,156],[22,20,140],[9,2,233],[137,135,214],[92,255,89],[139,207,2],[255,251,0],[255,196,0],[255,137,3],[255,43,0],[227,0,0],[161,0,0],[121,0,90],[250,172,209],[119,0,125]]
          boundaries = [0,.20,.45,.65,.75,.80,.85,.90,.93,.95,.96,.97,.98,.99,1.00,1.05]
  </code></pre>
  <p>and when I try to use matplotlib to plot the colors:</p>
  <pre><code>cmap_data = matplotlib.colors.ListedColormap(colormap)
  norm_cmap = matplotlib.colors.BoundaryNorm(boundaries,cmap_data.N,clip=True) 
  ...
  im = ax.pcolormesh(x,y,data,cmap=cmap_data,norm=norm_cmap)
  </code></pre>
  <p>I am getting some strange colors. For example, the second entry:</p>
  <p>[22,20,140]</p>
  <p>should be a dark blue color, but I am getting yellow (?). What might be wrong here.</p>