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.

tests: record few more daemon pids to be safe

tests: add timeouts, make run-tests.py clean up dead daemon processes test timeout feature is needed for test with python 2.5 beta. if test does not complete in time (30 seconds is default), it is killed. some times daemon process used in test can be alive after the test is killed by user or by timeout. tests now record daemon pids into $DAEMON_PIDS and run-tests.py kills all living daemons after every test. final little change is to add newline to end of pid file printed by "hg serve", else "cat hg.pid >> $DAEMON_FILES" gives garbage.

run-tests.py: make tests use same python interpreter as test harness. this is wanted because some tests run python interpreter directly. must use same python interpreter in tests as in main harness or problems will happen because of e.g. different python abi if run-tests.py run with python 2.5 but system python is 2.4. fix is to see if system python is used and is named python. if no, put symlink called python at front of shell search path.