[bind10-dev] consider log4cplus for logging

[Francis Dupont]

> It has been tested on various platforms including Windows.

=> I skipped it when I ported src/lib/log to Windows but
if the plan is to adopt it I can change this (BTW if the library
worked on Windows of course it doesn't work with syslog even there
are many ports of syslog to Windows, so log4cplus with a correct link
to Windows event system is the right way).

Thanks

Francis Dupont <fdupont at isc.org>