Allow for single values as well as lists for values in the CLI

Currently, if an argument takes a list, the parsing is primitive and requires the list be enclosed in brackets, e..g.

`  search >client_id -r .*localhost.* -out [home_url]
`
Improve the parsing so that the following works as well:
`
  search >client_id -r .*localhost.* -out home_url`
