Merge branch 'release/0.4.1' into develop
changed: session::set_timeout(0) will disable session timeout.

+ fixed: session timeout will invoke in *just* given seconds.
  ( originally, it invokes in given seconds +1 )
Merge pull request #3 from y-oda-oni-juba/feature/disable-session-timeout

support disabling session timeout.
Added a virtual destructor to msgpack::rpc::dispatcher.
Merge pull request #4 from gwtnb/virtual-destructor

Added a virtual destructor to msgpack::rpc::dispatcher.
update ChangeLog and bump version to 0.4.2
Merge branch 'release/0.4.2'