* The default verbosity level of all Nix commands is now lvlInfo.

* Builder output is written to standard error by default.
  * The option `-B' is gone.
  * The option `-Q' suppresses builder output.

The result of this is that most Nix invocations shouldn't need any
flags w.r.t. logging.

src/libutil/util.cc

@@ -243,7 +243,7 @@ void writeStringToFile(const Path & path, const string & s)
 
 
 LogType logType = ltPretty;
-Verbosity verbosity = lvlError;
+Verbosity verbosity = lvlInfo;
 
 static int nestingLevel = 0;