cf-download should support downloading a single file from the application

[lmsurpre]

The readme claims

Additionally, the path can point to a single file to be downloaded. Note: this works similarly to "cf files [path]".

However, I tried this today and got the following, not very helpful, error message:

> cf download letsencrypt /app/conf/live/ibmjstart.biz/cert.pem
[ Info: using .cfignore ]
0 :  Getting files for app letsencrypt in org [email protected] / space dev as [email protected]...

1 :  FAILED

2 :  Server error, status code: 404, error code: 0, message: 

Is it possible to support this use case?

cf files prints the file to the console, but redirecting it to a file would involve stripping the first couple lines off the output with sed (or similar)