Collective.recaptcha

----------------

- Fixed method signature for verify method so that the vestigial input parameter
from collective.captcha's ICaptchaView is no longer required.
[davisagli]

- Added documentation.
[davisagli]

------------------

- Correctly handle comma-delimited values in the HTTP_X_FORWARDED_FOR
header.
[davisagli]

- Added support for verifying the captcha multiple times within the same request.
[davisagli]

- Added security declarations on the view methods so they can be called from
restricted Python.
[davisagli]

------------------

- Initial release