The option '--check' checks for new mails without actually fetching
or deleting mail. Without '--check' 'debug-fetchmail' throws errors if
the external mail accout has new mails and the smtp daemon is not
running.
This commit adds a script nammed 'listmailuser'. './setup.sh' uses this
this script for its subcommand './setup.sh email list'. A test have
been added too.
* Wrote functional tests for desired behavior.
Redoing the pull request, starting from current master.
The tests now fail where expected.
* Updated commands to handle missing files better.
The functional tests now pass.
