* function pointer from a function should work also.
* make_function/make_constructor now return object instead of a raw pointer.
* module::setattr() now accepts anything which can be passed to object's constructor.
* Rework upcast<> to catch more errors at compile-time instead of infinite-looping.
* Rationalize class<>::def() in preparation for docstring support
* Partial docstring support in module::def (untested)
* dependent<> trick moved to detail namespace and separate header
* Added __doc__ attribute to C++ function wrapper objects
* Sunk implementation of function_object into a library source file.
[SVN r14724]
