Merge server-info into show-messages and remove some not useful output.
Support paste key in copy mode input (for search etc). Also clamp length
to screen width.
Merge start-server into kill-server.
Remember the last active pane in the top-bottom or left-right cell so
that it can be restored when moving back to that cell with selectp
-L/-R/etc. From Suraj N Kurapati.
Allow replacing each of the many sets of separate foo-{fg,bg,attr}
options with a single foo-style option. For example:

    set -g status-fg yellow
    set -g status-bg red
    set -g status-attr blink

Becomes:

    set -g status-style fg=yellow,bg=red,blink

The -a flag to set can be used to add to rather than replace a style. So:

    set -g status-bg red

Becomes:

    set -ag status-style bg=red

Currently this is fully backwards compatible (all *-{fg,bg,attr} options
remain) but the plan is to deprecate them over time.

From Tiago Cunha.
Fix missing argument, stupid last minute changes...
Add \033[18t window operations from J Raynor.
Fix partial matches with xterm-keys on, from m0viefreak dot cm at
googlemail dot com.
Break up and simplify screen_redraw_screen.