Add search and help to the captured output tool
Add SSKeychain as a dependency of iterm
Prevent capture triggers from firing more than once per line
Show an announcement when capture output fires without shell integration having seen a prompt yet in this session
Add support for multi-line announcements.
Show announcement when captured output is received but tool is not visible.
Improve captured output announcements
Use marks instead of line numbers for captured output locations. Generalize marks to an iTermMark base class and protocol.