MCO-429 update changelog and releasenotes for 2.6.0
MCO-429 Add documentation of SIGWINCH to daemon reference
MCO-429 Add references to activate_agents to docs
MCO-429 add registration_splay to docs
MCO-429 add client.cfg discovery_timeout to docs
MCO-429 add soft_shutdown_timeout to docs
Merge pull request #236 from richardc/MCO-429_2_6_0_release_notes

MCO-429 2.6.0 release notes and documentation