Merge pull request #76 from amitkgupta/master

Improve ConfusionMatrix GetSummary formatting, and several tiny improvements
Return error instead of panicking when unable to get confusion matrix
Trim the public interface of the edf package
Remove unused untested ParseCSV function
NewLogisticRegression returns error instead of nil to indicate error
Remove unused untested utility functions
Avoid renaming packages on import
Remove unused cross_validation package
Remove hardly-used logger
RandomForest returns error when fitting data with fewer features than the RandomForest plans to use

- BaseClassifier Predict and Fit methods return errors
- go fmt ./...

Conflicts:
	ensemble/randomforest.go
	ensemble/randomforest_test.go
	trees/tree_test.go
Convert some tests to goconvey, and improve assertions along the way