bos/critbit — pull request #72 by archblob (2013-06-13 15:39:23+00:00)
Title: Implement insertLookupWithKey and rewrite insert functions.

I rewrote all insert functions in terms of more general `` insertLookupGen ``` and we gain a little more speed.
The new benchmarks:
```
insert -- old
lower upper
Mean execution time	379.5 ns 400.6 ns
Standard deviation	27.08 ns	78.50 ns

insert -- new
lower upper bound
Mean execution time	296.7 ns 304.7 ns
Standard deviation	5.133 ns 30.69 ns
```