Create boat_sharing.svg
Create mm_amenity_boat_sharing.png
Update mm_amenity_boat_sharing.png

/Users/gilles/Documents/Map/osmand/mdpi/mm_amenity_boat_sharing.png
Delete mm_amenity_boat_sharing.png
icon for amenity=boat_sharing added

the icons for amenity=boat_sharing and the corresponding styles changes
were made.
Merge pull request #154 from nounours77/master

icon for amenity=boat_sharing added