Re-enabled debugging prints in poplib & documented the set_debuglevel()

method.
This closes SF patch #486079.

Doc/lib/libpoplib.tex

@@ -55,11 +55,19 @@ in lower-case; most return the response text sent by the server.
 An \class{POP3} instance has the following methods:
 
 
+\begin{methoddesc}{set_debuglevel}{level}
+Set the instance's debugging level.  This controls the amount of
+debugging output printed.  The default, \code{0}, produces no
+debugging output.  A value of \code{1} produces a moderate amount of
+debugging output, generally a single line per request.  A value of
+\code{2} or higher produces the maximum amount of debugging output,
+logging each line sent and received on the control connection.
+\end{methoddesc}
+
 \begin{methoddesc}{getwelcome}{}
 Returns the greeting string sent by the POP3 server.
 \end{methoddesc}
 
-
 \begin{methoddesc}{user}{username}
 Send user command, response should indicate that a password is required.
 \end{methoddesc}

Lib/poplib.py

@@ -96,14 +96,14 @@ class POP3:
 
 
     def _putline(self, line):
-        #if self._debugging > 1: print '*put*', `line`
+        if self._debugging > 1: print '*put*', `line`
         self.sock.send('%s%s' % (line, CRLF))
 
 
     # Internal: send one command to the server (through _putline())
 
     def _putcmd(self, line):
-        #if self._debugging: print '*cmd*', `line`
+        if self._debugging: print '*cmd*', `line`
         self._putline(line)
 
 
@@ -113,7 +113,7 @@ class POP3:
 
     def _getline(self):
         line = self.file.readline()
-        #if self._debugging > 1: print '*get*', `line`
+        if self._debugging > 1: print '*get*', `line`
         if not line: raise error_proto('-ERR EOF')
         octets = len(line)
         # server can send any combination of CR & LF
@@ -131,7 +131,7 @@ class POP3:
 
     def _getresp(self):
         resp, o = self._getline()
-        #if self._debugging > 1: print '*resp*', `resp`
+        if self._debugging > 1: print '*resp*', `resp`
         c = resp[:1]
         if c != '+':
             raise error_proto(resp)
@@ -205,7 +205,7 @@ class POP3:
         """
         retval = self._shortcmd('STAT')
         rets = retval.split()
-        #if self._debugging: print '*stat*', `rets`
+        if self._debugging: print '*stat*', `rets`
         numMessages = int(rets[1])
         sizeMessages = int(rets[2])
         return (numMessages, sizeMessages)