Release 0.13.4

Improvements:

• Improve GeoJSON data update #668
• Add support for WKT layer #679
• Add Gaode basemap #681
• Change SearchControl zoom trait to None #688
• Add example notebooks for KML and GPX file formats #691
• Update GeoData API documentation to add point_stype attribute #695
• Add a callback on found event for searching in GeoJSON layer #707
• Add custom tile server GIF to example notebook #724
• Add support for DivIcon #727
• Support for transparent WidgetControl #732
• Update LeafletJS from 1.3.0 to 1.7.1 #734
• Add Map.fit_bounds(bounds) #737
• Add MagnifyingGlass layer #733

Fixes:

• Add Shapely as a dependency #683
• Add nodejs dependency to Binder environment #700
• Set --minimize=False on Binder #704
• Remove class_name #729
• Change license to MIT #736
• Fix WMS layer options #755