Added last location to installations.  It is updated
when a new location is received.  It is not yet used.
Use the new last location columns in table installations.
Added checkboxes to showlostinst.php script to find locations
if the installations row does not have it, and to dispolay the
raw lat/lon or the address.
The getaddress script now uses the new last location
columns of table installations.
Retrieve accuracy from installations in getaddress.php.