Change version number from 1.1.0 to 1.2.0

VERSION

setup.py

splearn/__init__.py

splearn/automaton.py

splearn/datasets/data_sample.py

splearn/hankel.py

splearn/serializer.py

splearn/spectral.py

splearn/tests/datasets/get_dataset_path.py

splearn/tests/test_automaton.py

splearn/tests/test_base.py

splearn/tests/test_data_sample.py

splearn/tests/test_hankel.py

splearn/tests/test_serializer.py

splearn/tests/test_spectral.py