Add basic outdoor POIs

[nvkelso]

The following are basic features primarily with OSM node only data, suitable for POI layer only inclusion:

Format is:
LINK to osm wiki, EXAMPLE to construct test, recommended MIN_ZOOM value, and COUNT of features.

• aerialway=pylon, example - pois, zoom 17. Around 34,000 pois only.
• amenity=bbq, example - pois, zoom 18. Around 11,000 pois with 550 landuse / building (ignore).
• amenity=bicycle_repair_station, example - pois, zoom 18. Around 1350 pois, with 37 landuse/building (ignore).
• amenity=boat_rental, example - pois, zoom 16. Around 775 pois with 230 landuse/buildings (ignore).
• amenity=dive_centre, example - pois, zoom 16. Around 400 pois, with 100 landuse/buildings, need to prioritize amenity over building value in that case?
• amenity=life_ring, example - pois, zoom 18. Around 400 pois only.
• amenity=picnic_table, example - pois, zoom 18. Around 300 pois only.
• amenity=shower, example - pois, zoom 18. Around 7,600 pois, and 600 buildings (ignore).
• amenity=waste_disposal, example but avoid showing "private" features example 2 - pois , zoom 18. Around 31,000 pois, and 1200 landuse/buildings (ignore).
• amenity=watering_place, example - pois, zoom 18. Around 2200 pois, 300 landuse/buildings (ignore).
• amenity=water_point, pois example and 2, zoom 18. Around 5200 pois only.
• emergency=lifeguard_tower, example - pois, zoom 17. Around 69 pois, 37 buildings. For buildings, need to mark them as emergency value, not building value.
• power=pole, example related to Add powerlines #232 pois, zoom 18. Around 3,000,000 pois.
• power=tower, example related to Add powerlines #232 pois, zoom 16. Around 8,000,000 pois. 1100 building/landuse (ignore, they are either buildings or incorrectly tagged).
• [man_made=petroleum_well](http://wiki.openstreetmap.org/wiki/Tag:man_made%3Dpetroleum_well oil-well), example - pois, zoom 16. Around 34,000 pois, 600 landuse/buildings, should be coming thru as landuse=industrial if tagged correctly (ignore).

[nvkelso]

PR has everything except amenity=boat_rental, which is being tracked separately in #602.

[nvkelso]

Looking good.