Change NDEBUG to verbose logging

As requested in !90 (closed), I have renamed all debug and DEBUG to verbose (where it made sense), and renamed NLOGDEBUG to NOVERBOSELOG.

The logic is simple - most usually we want to have verbose logging compiled in and assert() (-DNDEBUG) not compiled in.

daemon/README.rst

@@ -73,7 +73,7 @@ The daemon features a CLI interface, type ``help()`` to see the list of availabl
 Verbose output
 --------------
 
-If the debug logging is compiled in, you can turn on verbose tracing of server operation with the ``-v`` option.
+If the verbose logging is compiled in, i.e. not turned off by ``-DNOVERBOSELOG``, you can turn on verbose tracing of server operation with the ``-v`` option.
 You can also toggle it on runtime with ``verbose(true|false)`` command.
 
 .. code-block:: bash