Update travis widget with new url
Merge pull request #33 from clusterpy/development

Development
Add viz function to show shapes with matplotlib

Now calling clusterpy.showshape(shape) or clusterpy.showshapes(shapes)
where shape and shapes are a layer object or an array of layer objects
respectively will present the shapes using matplotlibs pyplot.
This closes #14 but it's experimental
Add parameters to viz functions

Now I can specify the values for the colors, the color map (from the
matplotlib's colormaps) and the alpha for the colors.

The values for the colors is to give each area an 'intensity'. This
is useful to colorize a variable, so that the intensity of the color
represents the value of the variable.
Add information to the viz functions

information about the parameters and types
Add libraries to packages in setup.py

Add matplotlib to list of libraries for viz feature.