[boost] [circular_buffer] default constructor usually throws std::bad_alloc

I've attached a trivial patch to circular buffer which should allow it to be default constructed (and copy from an existing buffer) without making the default constructor cause an insane request to allocate a huge amount of memory (and fail to throw an std::bad_alloc). I personally think this is a show stopper bug in Boost 1.35.0 and the patch is distributed under the Boost C++ License Version 1.0. Should this be applied to be made part of 1.35.1? -- Dean Michael C. Berris Software Engineer, Friendster, Inc. [http://blog.cplusplus-soup.com] [mikhailberis@gmail.com] [+63 928 7291459] [+1 408 4049523]