Isolate formatted streaming blocks with clang-format off/on

The clang-format tool can do a good job formatting most code, but
well-organized streaming blocks are best left manually formatted.

Find blocks of the form

    os <<
      "...\n"
      "...\n"
      ;

using the command

    $ git ls-files -z -- Source |
      egrep -v -z '^Source/kwsys/' |
      xargs -0 pcregrep -M --color=always -B 1 -A 1 -n \
        '<<[^\n]*\n(^ *("[^\n]*("|<<|;)$|;)\n){2,}'

Find blocks of the form

    os << "...\n"
       << "...\n"
       << "...\n";

using the command

    $ git ls-files -z -- Source |
      egrep -v -z '^Source/kwsys/' |
      xargs -0 pcregrep -M --color=always -B 1 -A 1 -n \
        '<<[^\n]*\n(^ *<<[^\n]*(\\n"|<<|;)$\n){2,}'

Surround such blocks with the pair

    /* clang-format off */
    ...
    /* clang-format on */

in order to protect them from update by clang-format.  Use the C-style
`/*...*/` comments instead of C++-style `//...` comments in order to
prevent them from ever being swallowed by re-formatting of surrounding
comments.