A wrapper for 'libcurl' <http://curl.haxx.se/libcurl/> Provides
functions to allow one to compose general HTTP requests and provides
convenient functions to fetch URIs, get & post forms, etc. and process
the results returned by the Web server. This provides a great deal of
control over the HTTP/FTP/... connection and the form of the request
while providing a higher-level interface than is available just using
R socket connections.  Additionally, the underlying implementation is
robust and extensive, supporting FTP/FTPS/TFTP (uploads and
downloads), SSL/HTTPS, telnet, dict, ldap, and also supports cookies,
redirects, authentication, etc.