TableEditor: don't use REPLACE to update the content of a row.

TableEditor: don't use REPLACE to update the content of a row.

REPLACE deletes the row and then insert the new value. If the content of
the row is used as a foreign key by another table, this leads to a full
cleanup of all the entries that point to the deleted row... and when you
update the 'x' account_type, this removes all the accounts.

This also fix some minor programming errors:
 * let XDB perform the escaping, don't use addslashes manually.
 * don't call XDB('machin = {?} AND ' . $someStringContainingUserInput, $myvalue)
  (this is not critical since the placeholder is before the
  'random' string, but this can lead to errors if the 'random' string
  contain a placeholder {?}).

Signed-off-by: Florent Bruneau <florent.bruneau@polytechnique.org>