Instead of quitting the application immediately when the pty gives an
EOF, fire an on_command_exit hook so the TerminalWidget client can
decide for himself what to do.
Instead, have TerminalWidget provide an on_title_change hook.
This allows embedders to decide for themselves what to do if we receive
a "set terminal title" escape sequence.
When embedding a TerminalWidget, you might not want it to automatically
update its own size policy based on the exact terminal buffer size.
This behavior is now passed as a flag to the TerminalWidget constructor
which makes it behave nicely both inside HackStudio and in Terminal.
TerminalWidget was relying on the "window became active/inactive"
events from WindowServer to update its own internal focus state.
Unfortunately those events are only sent to the window's main widget,
so this was not working when the TerminalWidget was embedded deeper in
a widget tree.
This patch hooks the focusin and focusout events and uses those to
set the focus state when received. This makes TerminalWidget behave
nicely in both configurations. This design is kind of a workaround for
this awkward focus architecture and we should figure out something
better in the long term.
