Support for actions in qds-sdk

New API support for actions in sdk. This is useful to get the info of the pjus which have query_hist_id NULL under them
isn't unnamed argument required by default. eg:
[rgupta@localhost qds-sdk-py]$ qds.py action view  
usage: qds.py action view [-h] [--fields [FIELDS [FIELDS ...]]] id
qds.py action view: error: too few arguments

It works if I provide an id