Use a static graph for the example application

[waxlamp]

• A python script is provided that can generate bigram frequency for English
• The generated data has been added as an application asset
• The example application now displays a graph based only on this data
  • It is a graph on 26 nodes, each representing a letter of the English alphabet; a link goes from one letter to another if the frequency data shows that bigram to appear more often than chance
• A serious bug has been fixed, where in some cases, adding a neighborhood to the graph would not add the center of that neighborhood