Patch from Matsui Nag to implement xterm's "bracketed paste mode", in

Patch from Matsui Nag to implement xterm's "bracketed paste mode", in
which text pasted into the terminal is preceded and followed by
special function-key-like escape sequences ESC[200~ and ESC[201~ so
that the application can identify it and treat it specially (e.g.
disabling auto-indent-same-as-previous-line in text editors). Enabled
and disabled by ESC[?2004h and ESC[?2004l, and of course off by
default.

[originally from svn r9412]