Fixes issue #2

[mjuarezm]

There shouldn't be an overlap between the test and training sets. This fix declares a new constant TrainNum which corresponds to the number of instances for each class used for training. InstNum has the meaning of total number of instances for each class. We also need to modify the functions to parse the files so to select different ranges of instances for training and testing.

As expected, we obtain slightly lower accuracy scores:

2016/08/10 20:44:15 starting to learn distance...
distance... 5999 (0-6000)
2016/08/10 20:45:45 finished
2016/08/10 20:45:45 started computing accuracy...
accuracy... 11999 (0-12000)
2016/08/10 20:52:29 finished
2016/08/10 20:52:29 Accuracy: 0.806667 0.993667

[pylls]

Thanks a bunch 👍