Correct the placement of c-cpp-delimiters when there're #s not at col 0.

Correct the placement of c-cpp-delimiters when there're #s not at col 0.

        * progmodes/cc-langs.el (c-anchored-cpp-prefix): Reformulate and
        place a submatch around the #.
        * progmodes/cc-mode.el(c-neutralize-syntax-in-and-mark-CPP): Start
        a search at BOL.  Put the c-cpp-delimiter category text propertiy
        on the #, not BOL.