Save runtime config in solr.xml

* Completely load the "swiftriver" core on startup

* Explicitly set the data directory for the "swiftriver" core. This directory
is relative to the "instanceDir"
Index drop places data - refs #31

* A drops can reference more than one place entity therefore
use the "location_rpt" fieldType as it allows for multi-valued
spatial data. This is only available in Solr 4.0+
Refactor DropIndexService#populatePlaces

* Renamed the method to getDropPlaces that now returns
a java.util.Map<Long, List<String>> that contains a string
representation of the coordinates for the places associated
with each drop
Search queries by location bounds

* Implemented spatial search for drops in rivers and buckets.
This search is triggered by specifying a bounding box in the "locations" query
parameter. The bounding box should be specified as a set of latitude,longitude
pairs with the northwest corner of the bounding box coming first

* Closes #31
Spatial search improvements

* Ensure that the SouthWest corner of the bounding box is always
be specified first

* Doc blocks for the DropFilter.Bounding class
Merge pull request #36 from ushahidi/solr-dev

Spatial Queries