Added Timeseries example: issue #2024 (#2025)

* - Added Timeseries example:
  - SSVEPFormer for classification of EEG data for Brain-Computer
	Interface.
 On branch master
 Your branch is up to date with 'origin/master'.

 Changes to be committed:
	new file:   examples/timeseries/eeg_bci_ssvepformer.py

* - Updated the BCI SSVEPFormer example after pull request review
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 Your branch is up to date with 'origin/master'.

 Changes to be committed:
	modified:   eeg_bci_ssvepformer.py

* - Added files generated by the add_example command after PR review
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 Your branch is up to date with 'origin/master'.

 Changes to be committed:
	new file:   examples/timeseries/img/eeg_bci_ssvepformer/eeg_bci_ssvepformer_19_0.png
	new file:   examples/timeseries/img/eeg_bci_ssvepformer/eeg_ssvepformer_dataset1_interface.jpg
	new file:   examples/timeseries/img/eeg_bci_ssvepformer/eeg_ssvepformer_frequencypowers.png
	new file:   examples/timeseries/img/eeg_bci_ssvepformer/eeg_ssvepformer_keras_inference_time.png
	new file:   examples/timeseries/img/eeg_bci_ssvepformer/eeg_ssvepformer_keras_training_time.png
	new file:   examples/timeseries/img/eeg_bci_ssvepformer/eeg_ssvepformer_model.jpg
	new file:   examples/timeseries/ipynb/eeg_bci_ssvepformer.ipynb
	new file:   examples/timeseries/md/eeg_bci_ssvepformer.md

* - Edited the .md file after review.
 On branch master
 Your branch is up to date with 'origin/master'.

 Changes to be committed:
	modified:   examples/timeseries/md/eeg_bci_ssvepformer.md

* - Added newline at the end of fileX
 On branch master
 Your branch is up to date with 'origin/master'.

 Changes to be committed:
	modified:   examples/timeseries/eeg_bci_ssvepformer.py