Rename "App" Instane to AppInstance

The OTM1 version of this project referred to the global App
context as "Instance", but in OTM2, "Instance" refers to a
created tree map.  To avoid confusion, this existing term and
its associated methods have been renamed to AppInstance
Request configured Instance info

When an instnace name is supplied with the initial configuration
the app will attempt to retrieve information on that instance
immediately.
Update plot display from map tap

Copying the iOS version, I've removed dbh and last updated
from the tree info, and am now using the title property from
plot instead of species directly.  Begining to comment out
filter generation code which is broken for now.
Display plot details

Updates to conform to the OTM2 structure for plot/tree/species
Merge pull request #12 from OpenTreeMap/topic/map-instance

Map Instance and Plot Details