url: Added support for parsing login options from the CURLOPT_USERPWD

In addition to parsing the optional login options from the URL, added
support for parsing them from CURLOPT_USERPWD, to allow the following
supported command line:

--user username:password;options
tool_paramhlp: Fixed options being included in username

Fix to prevent the options from being displayed when curl requests the
user's password if the following command line is specified:

--user username;options
url: Added overriding of URL login options from CURLOPT_USERPWD