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##### SUMMARY
When I read the `copy` documentation, I couldn't work out what it meant.  Unfortunately, this meant it sounded like it might be a weird sex joke.

It doesn't sound like a big problem, but in an ideal world, I think we should prefer to avoid weird sex jokes in an alias for a parameter called `force`.

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
copy

##### ADDITIONAL INFORMATION
Issue search tells me "thirsty" was added as an option to the `get_url` module.  In that context, it is appropriate.  But in the context of the `copy` module, it does not make sense, because `copy` only works in the upload direction.

The first three pages of Google Search results (Ansible thirsty) show people using "thirsty" for downloads only, not uploads.  Similarly for GitHub code search (copy thirsty language:YAML).
- name: Download file with checksum url (sha256)
  get_url:
    url: http://example.com/path/file.conf
    dest: /etc/foo.conf
    checksum: sha256:http://example.com/path/sha256sum.txt
- name: Download file from a file path
  get_url:
    url: file:///tmp/afile.txt
    dest: /tmp/afilecopy.txt
- name: < Fetch file that requires authentication.
        username/password only availabe since 2.8, in older versions you need to use url_username/url_password
  get_url:
    url: http://example.com/path/file.conf
    dest: /etc/foo.conf
    username: bar
    password: '{{ mysecret }}'
'''
RETURN = r'''
backup_file:
    description: name of backup file created after download
    returned: changed and if backup=yes
    type: str
    sample: /path/to/file.txt.2015-02-12@22:09~
checksum_dest:
    description: sha1 checksum of the file after copy
    returned: success
    type: str
    sample: 6e642bb8dd5c2e027bf21dd923337cbb4214f827
checksum_src:
    description: sha1 checksum of the file