Removed extra "reduce" statements.

min supports lists directly, so reduce(min, rater_a) was verbose (and potentially less efficient).

I also improved the PEP8 compliance by getting rid of TABs used for indentation and adding spaces around operators.
Fixed divide by zero error in average precision
added KDD version of MAP@K for the python implementation
added KDD version of MAP@K for the python implementation
Added capped_binomial_deviance
added custom metrics
now ignoring .DS_Store files
Fixed float bug in calculating num_ratings
Updated gitignore to account for C#
Started C# Metrics
more infastructure
blah
Added NUnit
Added reflection + app
Added MAE
Reworked metric reflection / scoring
Added weightedmeanquadraticweightedkappa python
a
now can do normalized levenshtein distance
added travis-ci as continuous integration server