fix docstrings and typos

[jakobgemassmer]

Changes proposed in this pull request:

• Adjusted docstrings to appear in RTD in correct way.
• Fixed minor typos.

The following steps were realized (required):

• [x] Correct linting with flake8 path_to_script
• [x] Check if tests pass locally with python -m pytest tests/

Also the following steps were realized (if applies):

• [x] Write docstrings to your code
• [x] Explain new functionalities in readthedocs
• [ ] Write test(s) for new patch of code
• [x] Check building of documentation with doc/make html