Support houses for rent

Avoid 509 errors from kalaydo

Fix import order

Ensure the kalaydo spider fetches all houses, keep old houses that weren't fetched

Fix indentation

Ignore HTTP 509 errors from Kalaydo

Fix kalaydo spider

Fix immobilienscout24 spider

Improve the README

Remove unnecessary coding declaration

Make spiders configurable and easier to add

Print the address first, and print the price only when available

Properly encode the address

Store and print the address of each house

Ignore the rooms when checking for duplicates