[boost] [MPL] web doc suggestion.

Hi, From: http://www.boost.org/doc/libs/1_45_0/libs/mpl/doc/refmanual/classes.html, it's not readily apparent that in addition to vector_c, list_c, set_c, there are also vector, list, and set classes. I suggest also mentioning and linking to them in the aforementioned url. Thanks, Mostafa