fixed typo and number calculation resulting in NaN when no results to show
Created script to load the twitter data source
Made twitter data source take a max of 50 tweets
add rescue on InvalidURIError
Created the WeightFunction and UniformWeightFunction classes
add requires to lib/phisher
removed weight parameter from Algo and added instead the WeightFunction as a more modular approach to the weighting problem
Fixed broken specs and typo in WeightFunction
Fixed broken phisher_spec

1. Fixed several typos (weight/weigth)
2. Created BlockWeightFunction
3. Fixed several issues in phisher_spec
added documentation to CachedDataSource