Add an option to load a session without attaching to it.
Merge pull request #43 from roxit/detached

Add an option to load a session without attaching to it.
more args.detached conditions.
Add tmux 1.8 installation instructions for Ubuntu 12.04/12.10/13.04.
Prepare to tag v0.1.2, Update changelog.
Merge pull request #44 from roxit/ubuntu-tmux

Add tmux 1.8 installation instructions for Ubuntu 12.04/12.10/13.04.