[#1179] add offset/limit to package_list action
[#1179] Add test for limit in package_list
[#1179] doc strings for package_list
Merge remote-tracking branch 'origin/1179-package_list_limit_offset' into 1179-package_list_limit_offset
Merge pull request #1179 from okfn/1179-package_list_limit_offset

add limit/offset to package_list action