itermocil launch fails when broadcast input is enabled

[jranson]

If i run itermocil when i have broadcast input, the launch fails and i have to close the windows, disable broadcast input, run itermocil again, and re-enable broadcast input. The itermocil application should be able to gracefully handle the broadcast input toggle (e.g., check for it, and temporarily disable it when launching the layout).

[newbery]

shift+command+i Toggle broadcast to all tabs option+command+i Toggle broadcast to current tab

If you limit broadcast to current tab, you should have no issue when itermocil opens a new tab.

(possibly a feature available only on iTerm 3+)