Pyjibe

- fix: missing title in FD window and missing FD number in export menu
- enh: add help menu with link to docs, about, and software used (1)
- docs: add quick guide for importing a nanite training set
- docs: add black/white logo

- feat: allow to import training sets produced with nanite
- ref: major code refactoring of force-distance interface and cleanup
- setup: bump nanite dependency to >=1.1.1

- ci: pin 'joblib==0.11.0' on travis-CI (workaround for infinite loop
in macOS build, https://github.com/pyinstaller/pyinstaller/issues/4067)
- docs: add installation instructions

- maintenance release (migrate to GitHub infrastructure)
- experimental macOS builds

- enh: merge training set and regressor selection into scheme selection
(prevents confusion for users that are unsure what to choose)
- enh: user rating is saved during rating, not afterwards
- enh: rating containers for user rating can be reused explicitly
- enh: qmap plot now better distinguishes between unavailable and
invalid data
- ref: migrate user rating output to nanite

- fix: autoscaling according to fitting range did not work
- fix: not possible to load .jpk-force-map files
- ref: migrate qmap generation to nanite