Merge branch 'tutorial' into 'master'

.gitignore

README.rst

img/beat_editor_home.png

img/iris_db_overview.png

img/iris_flowers.jpg

img/iris_versicolor_measurements.png

img/toolchain_scale_and_lda.png

prefix/databases/atnt/4.json

prefix/databases/atnt/4.py

prefix/databases/atnt/4.rst

prefix/databases/atnt/6.json

prefix/databases/atnt/6.py

prefix/databases/atnt/6.rst

prefix/databases/iris/2.json

prefix/databases/iris/2.py

prefix/databases/mnist/4.json

prefix/databases/mnist/4.py

prefix/databases/mnist/4.rst

prefix/databases/mobio/4.json

prefix/databases/mobio/4.py