Clarify `mask` argument in `medial_axis` docstring
Update parameter list in docstring for consistency
Merge pull request #1022 from jni/medial_axis

Clarify `mask` argument in `medial_axis` docstring
Use more recent NoNorm API
Correctly compare mask to None
Ignore auto-generated notebooks in Git
Fix median filter example
Merge pull request #1026 from stefanv/bugs/watershed_none_comparison

Correctly compare mask to None
Merge pull request #1025 from stefanv/compat/painttool_mpl_NoNorm

Use more recent NoNorm API
Merge pull request #1027 from stefanv/maint/ignore_generated_notebooks

Ignore auto-generated notebooks in Git
Merge pull request #1028 from stefanv/viewer/median_filter

Fix median filter viewer example
Use same order as matplotlib for PySize/PyQT
Merge pull request #1024 from stefanv/bugs/qt_pyside_matplotlib_compat

Use same import order as matplotlib for PySide/PyQT
Update label2rgb doc
Split label2rgb into two related functions
Add background label handling for label2rgb_avg
Add docstring for _label2rgb_avg
Add default values for background in _label2rgb_avg
Add docstring for _label2rgb_overlay
Add tests for label2rgb avg mode