implemented suggested changes

eval/plot.py

eval/run.sh

eval/step_configs/config_femnist_100.ini

eval/step_configs/config_femnist_fft.ini

eval/step_configs/config_femnist_sharing.ini

eval/step_configs/config_femnist_topkacc.ini

eval/step_configs/config_femnist_wavelet.ini

eval/testing.py

setup.cfg

src/decentralizepy/models/Model.py

src/decentralizepy/node/Node.py

src/decentralizepy/sharing/FFT.py

src/decentralizepy/sharing/PartialModel.py

src/decentralizepy/sharing/TopK.py

src/decentralizepy/sharing/Wavelet.py

src/decentralizepy/training/ChangeAccumulator.py

src/decentralizepy/training/FrequencyAccumulator.py

src/decentralizepy/training/FrequencyWaveletAccumulator.py

src/decentralizepy/training/ModelChangeAccumulator.py