Map markers for obscured observations should be stemless and sometimes located using private_lat private_lon

[loarie]

On the explore tab, like the website, some logic should be used on the observation data to choose the location in which a marker is mapped (ie whether they use lat/lon or private_lat/private_lon) and and to choose to display a stemmed or stemless marker.

using observation data e.g. looking at http://www.inaturalist.org/observations/744349.json
the logic to position the marker should be (@kueda please check this):

if private_latitude: nil ?
plot marker at latitude/longitude
else
plot marker at private_latitude/private_longitude
end

the logic to plot a stemmed vs. unstemmed marker should be:

if coordinates obscured: true
plot stemless marker
else
plot stemmed marker
end

here's an example on the website of stemmed/unstemmed markers for a search that includes observations mapped as both:
http://www.inaturalist.org/observations?utf8=%E2%9C%93&q=&search_on=&quality_grade=any&place_id=&swlat=37.68471175959279&swlng=-122.71736017871098&nelat=37.955914776445056&nelng=-122.27790705371098&taxon_name=Lessingia&taxon_id=56969&day=&month=&year=&order_by=observations.id&order=desc&rank=&hrank=&lrank=&site=&tdate=&d1=&d2=&filters_open=true&view=map

[loarie]

Checking in on this old issue I made -
There are 3 things relating to this issue that prob still need attention:

1. User should see 'private version' of obscured obs for all observations they have access to (e.g. their obs, and obs shared with projects they curate) currently User can only see private version for their obs
2. 'private' version should be positioned on private lat/lon, currently they are positioned on public lat/lon (for example when I search for my observations of a threatened species I see stemmed markers but they are positioned on the public lat/lon)
3. See Revisit Cartography conventions inaturalist#599 for proposal about how to display open vs. obscured obs on these maps