requirements: Added "sphinx" dependency for development
docs: Added generated sphinx-quickstart output
docs: Added _themes submodule

from https://github.com/Turbo87/flask-sphinx-themes.git
docs: Activated flask theme
docs: Adjusted theme options
docs: Removed sphinx-quickstart header comment
TravisCI: Fixed flake8 call

Don't lint the docs folder. The theme has some issues with flake8.
docs: Added logo
Added CHANGELOG file
docs: Added basic documentation
Merge pull request #2 from Turbo87/sphinx

Sphinx documentation
Merge branch 'master' into igc-writer
igc/writer: Fixed write_gps_datum() method
igc/writer: Added docstrings
docs: Added aerofiles.igc to api documentation