When debug is off, line 662 in function NNTP.prototype._send gave an error.
NNTP.prototype._debug is called as a function, while it is a boolean.
NNTP.prototype._debug is now tested as a boolean first on line 662
Merge pull request #12 from dporru/master

When debug is off, line 662 in function NNTP.prototype._send gave an error