`triton package help list` supported fields not accurate

The list of supported fields as shown in the output of triton package help list do not match what node-triton considers valid filters or what is available to CloudAPI.

$ triton package help list
[snip]
Filters:
    FIELD=VALUE        Field equality filter. Supported fields:
                       account, owner, state, name, os, and type.
[snip]

Attempting to filter on account, owner, state, os, or type will return an "invalid filter name" error:

$ triton package list account=foo
triton package list: error (Usage): invalid filter name: "account" (must be one of "name", "memory", "disk", "swap", "lwps", "version", "vcpus", "group")
usage: triton package list [FILTERS]

Inspect lib/do_package/do_list.js around the valid-filter definition and the help text near line 184. Compare both with the CloudAPI ListPackages fields, then run triton package help list and the package-list filter example to verify that the displayed supported fields match accepted filters.