0.2.0

Added

• A hint in the documentation about implementing AutoTransIter for references.
• TransPrioQueue, a transitive priority queue, and functions for creating such
  a queue from a TransIter, including documentation and a test.
• Examples illustrating the use of the library's iterators for shortest-path
  searches.

Changed

• Items referred to in documentation text are now actual references.
• A confusing piece of documentation regarding a blanket implementation was
  rewritten.
• The test tests::node_order_breadth_first was rewritten for better
  performance (but still takes significantly more time than any other test).

Initial release

Initial version of TransIter and utilities, with tests.

Don't expect too many changes from here on.