kahansum equals zero for empty vec.
implements more accurate summation in the normalization function in the comp map class
prefer prepended iterator
prefer prepended iterator
prefer prepended iterator
prefer prepended iterator
prefer prepended iterator
prefer prepended iterator
Passing references to boost shared pointer instances is ill-advised and disables the guarntee that the shared pointers were created in order to fulfill. This upgrades all functions in which a const CompMap& is passed rather than a CompMapPtr. http://stackoverflow.com/questions/327573/c-passing-references-to-boostshared-ptr.