Glacier-lengths

Updated version consistently on all platforms.

Fixed issues with pypi and conda-forge

New features:
- 1 Added warning if cutting geometry does not cut all centerlines
- 5 Added modifiable minimum distance threshold in cut_centerlines()

Fixes:
- 4 Fixed outline and centerline plotting kwargs being incorrectly switched
- 6 Fixed Shapely deprecation warnings in recent shapely versions

Bumped versions

Added conda capabilities.

* Improved documentation.
* Added examples loading structure.
* Hid some utility functions from the public API