removed preliminary work

preliminary /requirements.txt

-# Environment for 2-D MaskedAutoregressiveFlow
-
-absl-py==0.13.0
-appnope==0.1.2
-argon2-cffi==20.1.0
-astor==0.8.1
-async-generator==1.10
-attrs==21.2.0
-backcall==0.2.0
-bleach==3.3.1
-cached-property==1.5.2
-certifi==2021.5.30
-cffi==1.14.6
-cycler==0.10.0
-debugpy==1.3.0
-decorator==5.0.9
-defusedxml==0.7.1
-entrypoints==0.3
-et-xmlfile==1.1.0
-gast==0.2.2
-google-pasta==0.1.7
-grpcio==1.38.1
-h5py==3.3.0
-importlib-metadata==3.10.1
-ipykernel==6.0.2
-ipython==7.25.0
-ipython-genutils==0.2.0
-ipywidgets==7.6.3
-jedi==0.18.0
-Jinja2==3.0.1
-joblib==1.0.1
-jsonschema==3.2.0
-jupyter==1.0.0
-jupyter-client==6.1.12
-jupyter-console==6.4.0
-jupyter-core==4.7.1
-jupyterlab-pygments==0.1.2
-jupyterlab-widgets==1.0.0
-Keras-Applications==1.0.8
-Keras-Preprocessing==1.1.2
-kiwisolver==1.3.1
-Markdown==3.3.4
-MarkupSafe==2.0.1
-matplotlib==3.4.2
-matplotlib-inline==0.1.2
-mistune==0.8.4
-nbclient==0.5.3
-nbconvert==6.1.0
-nbformat==5.1.3
-nest-asyncio==1.5.1
-notebook==6.4.0
-numpy==1.21.1
-openpyxl==3.0.7
-opt-einsum==3.3.0
-packaging==21.0
-pandas==1.3.0
-pandocfilters==1.4.3
-parso==0.8.2
-pexpect==4.8.0
-pickleshare==0.7.5
-Pillow==8.3.1
-prometheus-client==0.11.0
-prompt-toolkit==3.0.19
-protobuf==3.17.3
-ptyprocess==0.7.0
-pycparser==2.20
-Pygments==2.9.0
-pyparsing==2.4.7
-pyrsistent==0.18.0
-python-dateutil==2.8.2
-pytz==2021.1
-pyzmq==22.1.0
-qtconsole==5.1.1
-QtPy==1.9.0
-scikit-learn==0.24.2
-scipy==1.7.0
-Send2Trash==1.7.1
-six==1.16.0
-sklearn==0.0
-tensorboard==1.15.0
-tensorflow==1.15.0
-tensorflow-estimator==1.15.1
-termcolor==1.1.0
-terminado==0.10.1
-testpath==0.5.0
-threadpoolctl==2.2.0
-tornado==6.1
-traitlets==5.0.5
-typing-extensions==3.10.0.0
-wcwidth==0.2.5
-webencodings==0.5.1
-Werkzeug==2.0.1
-widgetsnbextension==3.5.1
-wrapt==1.11.2
-xlrd==2.0.1
-zipp==3.5.0