add scan_full_status method
add formated_report_download
don't forget additional dependency
load HTML::Parser only if needed
additional server response check
use response lenght rather than content-type

Content-type header doesn't allow to distinguish between final response
in HTML format, and intermediate server response.
use tabs for indentation, for consistency
Merge pull request #2 from guillomovitch/master

Nessus::XMLRPC (corrected) - scan_full_status and formatted report download