Test positional arguments with underscores
Fix for positional arguments with underscores

Positional arguments with underscores are flagged as positional by storing the
name *with* the underscore in a list. However, the flag is set somewhere else
in the code, where the underscore has been replaced for a dash. Hence, the
positional test fails and the task argument is left in a weird limbo of not
being neither positional nor optional.

The fix is easy: simply move the positional and optional tests to before the
name change happens :)
Merge branch 'master' into 128-int
Changelog re #128
Fix occasional ordering related test fails on py3