Ensure strings are properly formatted
Make _execute_system_command avoid invoking the shell

That way arguments don't have to be escaped carefully.  Escaping strings
for the shell is difficult and almost everyone gets it wrong in some
subtle way.  IPC::System::Simple never invokes the shell and so avoids
the issue entirely.
Added UR_DBI_NO_COMMIT to Notable.t

It seems someone added the entities it creates to the database by
mistake somehow.