namespace: drop most boost namespaces and a few header cleanups

A few boost::asio were left around because they're very wordy otherwise.

src/test/bloom_tests.cpp

@@ -20,7 +20,6 @@
 #include <boost/tuple/tuple.hpp>
 
 using namespace std;
-using namespace boost::tuples;
 
 BOOST_AUTO_TEST_SUITE(bloom_tests)