Merge pull request #26 from emirpasic/btree

Btree

Merge pull request #25 from emirpasic/treebidimap

TreeBidiMap

Merge pull request #23 from emirpasic/bidi_map

- bidimap implemention as dual hashmap bidirectional map

Merge pull request #20 from emirpasic/iterator_reset

Iterator Reset

Merge pull request #18 from emirpasic/reverse_iterator

Reverse iterator

Stable version that matured for a year with addition of Iterators and…

… Enumarables