- change click-by-click advice on modifying saved sessions
- add `Restart Session' as another reason you might not want to close the
window on exit; other tweaks to this language
- mention Shift-Backspace action
- the window resizing configuration documentation was completely out of
date; rewrite
- add a note about Default Bold Background since it's caused confusion
- "remote terminal" -> "remote system" in terminal-type doc
[originally from svn r4686]