Add a README to briefly explain where this asio came from.

git-svn-id: svn://bind10.isc.org/svn/bind10/trunk@2655 e5f2f494-b856-4b98-b285-d166d9295462

Makefile.am

@@ -41,8 +41,8 @@ report-coverage:
 coverage: clean-coverage perform-coverage report-coverage
 
 #### include external sources in the distributed tarball:
-# EXTRA_DIST = ext/asio/README
-EXTRA_DIST = ext/asio/asio/local/stream_protocol.hpp
+EXTRA_DIST = ext/asio/README
+EXTRA_DIST += ext/asio/asio/local/stream_protocol.hpp
 EXTRA_DIST += ext/asio/asio/local/basic_endpoint.hpp
 EXTRA_DIST += ext/asio/asio/local/datagram_protocol.hpp
 EXTRA_DIST += ext/asio/asio/local/connect_pair.hpp

ext/asio/README

@@ -0,0 +1,5 @@
+ASIO library header files
+Version 1.4.5 (2010-05-12)
+Downloaded from http://sourceforge.net/projects/asio/files
+Project page: http://think-async.com/Asio
+No local modifications.