Adding PCAVariance feature
small refactoring for number of PCA/ICA components
Merge pull request #19 from gianba/pca_variance_feature

Adding PCAVariance feature
Factorisation

- Use variable data as it might be raw eeg, ica or pca data
- Factor out the number of features beforehand
Prepare eeg filtering test

- Use only frequency features for the test
Return original signal for further analysis
Add signal package
Filter raw clip data frequencies above 70Hz
Fix filtering

- Get sampling frequency from data clip
Remove comments
Factor out filtering method