fix problems with external module handling. found by benoit boissinot.
first fix is to not store module objects in commands.external dict,
instead use module names for key into sys.modules. this prevents circular
reference during cleanup of aborted transaction.
second is to get name right during import of external module.
#header#
<div class="page_nav">
<a href="?cmd=summary;style=gitweb">summary</a> | <a href="?cmd=changelog;style=gitweb">log</a> | <a href="?cmd=tags;style=gitweb">tags</a> | <a href="?cmd=manifest;manifest=#manifest#;path=/;style=gitweb">manifest</a><br/>
#changenav%naventry#<br/>
</div>
<table cellspacing="0">
#entries#
</table>
#footer#