logger: Moved to blackhole
thevoid: Added request_id and trace support
thevoid: Introduced thevoid::http_*

They are more specific replacement for general-purpose swarm::http_*
thevoid: Fixed config for trace_header
thevoid: Pass more arguments to http_request

They are: local_endpoint, remote_endpoint, request_id, trace_bit
both: Moved to blackhole's platform detection
thevoid: Changed close's semantic

Now it's synchronous if possible and should be used as 'send_data'
functions, so it's normal to call send_data several times and right
after them to call close, instead of adding close call in handler of
last write
swarm: Fixed initalizing of url_fetcher's logger
thevoid: Don't forget to reset boolean flags
thevoid: Logger fixes
urlfetcher: Removed pimpl member from http_* successors
urlfetcher: Make class movable, fixed destructor
swarm: Fixed memory leak
urlfetcher: Stop timer on negative timeout
v0.7.0.0