Fixes issue 5375.

When creating a new tab using the default profile when the current tab is a tmux tab, refer to the gateway session's current directory for the purposes of recycling the working directory. Issue 5320

session-closing confirmation, only show the kill/hide confirmation.
However, when closing a window, we still show both because kill/hide
doesn't offer cancel.

Fix a bug where a maximized tmux pane's contents would appear behind a per-pane titlebar. setSizesInTmuxParseTree incorrectly assumed there would be no title bar when there was only one pane, but a maximized pane retains its titlebar.

Fix a crash where selection/mark ranges has length 0 prior to trimming. Not sure what the cause was, but it's better to tolerate it and drop the subselection/mark than assert and die

Modernize reloadBookmarks slightly to try to fix a crash in isEqualToString: in reloadBookmarks when you change a session's profile from Edit Session

Fix some analyzer complaints leading to a memory leak and bad distance computations.

Keep a pool of webviews around since they never get deallocated. This helps keep their numbers down.

Stop WKWebView from playing media when quicklook is closed. The webview is leaked, but I don't see that I'm doing anything wrong here. All the references to it according to the memory debugger are from internal objects that I can't affect directly.

Fix imgcat support for PDFs, which have no pixel size in their NSImageRep and need to create temp files in /private/var.

If state restoration gives us an inconsistent state then CharToStr can return nil, which makes appendString: raise an exception. A colleague ran into this issue causing repeated crashes when restoring a tmux session.

5258.

didn't check their length when the system framework does segmentation. This
could cause buffer overruns as seen in issue 5223.

When entering a password, if an asterisk is echoed back, accept that you're at a password prompt. Issue 5235

Fix image decoder on older OSes: Remove uses of 10.11 base64 APIs and fix sandbox permissions for 10.8.

Also uses the bitmap rep's dimensions instead of NSImage's dimensions, which are not always pixels (e.g., png can specify physical dimensions with the OS uses to scale the image down).

Only attempt "tmux recovery mode" (where a fake DCS code is sent internally to restart tmux integration on window restoration) if we successfully attach to a file descriptor server.

Block SIGPIPE in file descriptor server. It looks like macOS 10.12 broke syslog: when the parent process dies, syslog tries to write to a broken pipe.

The the tmux profile's background color but a little lighter/darker for the flexible view. Issue 4863.

row when there was a horizontal split. Issue 5233.