sonograms added

added and some tex written to explain the sounds
conflict corrected
spectrogram

i have written a little chapter that explain that the chose of the sound
is from some of the articles and that presents the spectrograms
Merge pull request #15 from RasmusBlind/rasmus-sonogram

Rasmus sonogram
KNN updata
Merge pull request #16 from RasmusBlind/rasmus-knn

KNN updata
Branch updated with master