Add whitewater putin, egress, and hazard to POIs layer

[nvkelso]

pois layer:

• whitewater=putin, zoom 14
• whitewater=egress, zoom 14
• whitewater=hazard, zoom 15
• whitewater=put_in;egress, zoom 14, but with kind of put_in_egress
• whitewater=rapid, at zoom 15.

roads layer:

• whitewater=portage_way is primarily ways (not nodes). Let's try adding those to the roads layer under the general path High Road moniker, but with whitewater:portage_way details. Show them when paths show.

See also:

• http://wiki.openstreetmap.org/wiki/Key:whitewater/Proposal
• https://www.openstreetmap.org/node/2356117215

[rmarianski]

There are some other tag combinations, with the most popular being whitewater=rapid. Should those be included too? See taginfo.

[nvkelso]

I'm down for also adding rapid, at zoom 15.

portage_way is primarily ways. Let's try adding those to the roads layer under the general path High Road moniker, but with whitewater:portage_way details.

The others seem long tail that we can ignore for now.

I've updated the zoom range recommendation in the primary issue description, too.

[nvkelso]

Not seeing example whitewater POIs in Europe :\