Import improvements
Import improvements

Do the whole thing in a transaction so that we don't have downtown when things are deleted.
Remove old data before importing to ensure that we outdated stops, etc no longer show up.
Remove find_or_initialize blocks because those are only run when initialize is done and updates
weren't being run in the update case.

Signed-off-by: Geoff Lane <c3918f39022407dee6a0056ceca9b1aa80e8e4ce@zorched.net>

bus-detective/bus-detective,bus-detective/bus-detective,gaslight/bus-detective,gaslight/bus-detective,bus-detective/bus-detective,gaslight/bus-detective,gaslight/bus-detective,bus-detective/bus-detective