Merge pull request #167 from Klaim/master

Logging improvements: options & custom log record handling
Move streaming to a log_record method because to remove use of non-standard rvalue binding to a non-const lvalue reference.
Merge pull request #169 from imaginaryboy/master

Fix build with clang on OS X
log_record now don't log on destruction, logging macro will.
Merge branch 'master' of https://github.com/Klaim/cpp-netlib

Conflicts:
	include/network/detail/debug.hpp
Merge branch 'master' of github.com:pibara/cpp-netlib

Conflicts:
	include/network/detail/debug.hpp