New smart pointer documentation. Related clean-up of the smart pointer

library. Changing includes to include the new individual smart pointer
headers. Replacing old smart pointer library with an include of the new
smart pointer headers. Simplify ifdefs that involve the member templates
macros now that BOOST_MSVC6_MEMBER_TEMPLATES is also guaranteed to bet
set for platforms that have full member templates.


[SVN r12647]

shared_ptr_example2.cpp

@@ -17,5 +17,3 @@ example & example::operator=( const example & s )
 
 void example::do_something()
   { std::cout << "use_count() is " << _imp.use_count() << "\n"; }
-
-example::~example() {}