archery 0.2.0

• Added some functionality to SharedPointer that you would expect from Rc/Arc.
  • Functions:
    • SharedPointer::try_unwrap().
    • SharedPointer::get_mut().
    • SharedPointer::strong_count().
    • SharedPointer::ptr_eq().
  • Traits:
    • Default.
    • From<T>.
    • From<Box<T>>.
    • std::fmt::Pointer.