0.3
* BREAKING: change the name of insert_sorted to insert_many
* add update, and update_many
* insert 14% performance improvement
* insert_many 42% performance improvement on unsorted data, now faster than insert on random data

0.2.1
* BREAKING: change signature of insert to match BTreeMap as closely as possible. Sorry I was new to rust when I first wrote this module :-(

0.2.0
* iteration runs in constant space
* Implement collection range api
* Implement DoubleEndedIterator
* insert_sorted performance improved on degenerate cases
* BREAKING: insert_sorted now takes IntoIterator instead of an explicit slice
* BREAKING: change the name of length to len, like BTreeMap

0.1.2
Initial public release
