backup/nopasswords MDL-20383 Backups are now never saved with user passwords unless the admin has defined $CFG->includeuserbackupsinpasswords in config.php  (Merged from 1.9)   Credits to Eloy

this is the first step in moving towards supporting multiple exports per session.

however, some plugins aren't going to be able to support this (eg box.net) so
we add the instance to the tempdata table, so that we can quickly check whether
we have an export of the same *type* of plugin in the session.

this disambiguates, so we can have a function called allows_multiple_exports

since we can construct whatever return url we want.

thanks to Daren Chandisingh for the patch

Thanks to Michael Ahenerne/Daren Chandisingh for the patch

Even though the visible column is going to be dropped,
we need to set it here or the query at line 2087 will fail.

Huge thanks to Oleg Sychev who did all the debugging and testing for this fix.

webservice MDL-17135 Add some Zend library needed for Amf + add one line in order to set amf server in development mode