job main loop: another round of functional test timeout adjustment

Looks like a travis worker can be a lot slower than I thought at first,
in the order of 50 times slower than a 2 year old development machine.

So now, the timeout is 250 times higher than the test run would take
under the mentioned development machine (0.12s), but still able to
catch bugs if the loop does not cycle immediatelly on failure for the
100 failtests.

Signed-off-by: Cleber Rosa <crosa@redhat.com>
avocado.cli.app: Fix to display all --help options.

Fix the way that we handle argument parsing, to display
all options for subcommands when --help is passed.

We fix the problem by using parents parse.

Plus: cosmetic fixes in avocado.plugins regarding
argument parse.

Signed-off-by: Ruda Moura <rmoura@redhat.com>
Merge pull request #146 from ruda/fix_help_option

avocado.cli.app: Fix to display all --help options.