add configurable contact email for error pages

tests/functional_tests.py

@@ -14,6 +14,8 @@ def test_page_that_doesnt_exist(client):
     response = client.get('/ohuesthaoeusth')
     assert response.status_code == 404
     assert b'<b><tt>/ohuesthaoeusth</tt></b> does not seem to exist' in response.data
+    # test the contact email config
+    assert b'bss@incorporeal.org' in response.data
 
 
 def test_files_outside_pages_do_not_get_served(client):
@@ -28,6 +30,8 @@ def test_internal_server_error_serves_error_page(client):
     response = client.get('/actually-a-png')
     assert response.status_code == 500
     assert b'INTERNAL SERVER ERROR' in response.data
+    # test the contact email config
+    assert b'bss@incorporeal.org' in response.data
 
 
 def test_weird_paths_do_not_get_served(client):