Merge branch 'introduction_station_averaging' into 'testing'

updated version, we might declare the release as a new version

See merge request !33

CHANGELOG.md

 # Changelog:
 Adding of notable and major changes.
 
+## until 0.4.5
+- Fixed bug in loading of station metadata leading to invalid coordinates
+- added option to average all timeseries at a station before the gridding
+- update of contributors endpoint to the now ready implementation of the contributors service of the TOAR-DB
+- rework of contributors classes
+- fixed issue in download of package from gitlab via pip
+- enhancements to documentation
+- added option to extend history (e.g. when using TOAR gridding within a service)
+
 ## 0.3.0 Preparation of PiPY release.
 
 ### Project structure