Trying to use Boost ASIO endpoints for IPv6.
Bind IPv6 addresses only.
Drop an unneeded CMake flag.
Merge branch 'master' into boost-asio-endpoints

Conflicts:
	include/cocaine/asio/local.hpp
	include/cocaine/asio/tcp.hpp
	include/cocaine/asio/udp.hpp
	src/app.cpp
	src/context.cpp
	src/locator.cpp
Use ASIO resolver instead of my own crippled one.
Minor code beautifulization.
Properly handle resolver errors.
Try every possible endpoint when adding a new node.
Some additional verbosity in the Locator.
Development version bump.