till-s

Results 2 issues of till-s

kb_itr_get() has a bug as proven by the attached test program [kbtree_itr_test.c.zip](https://github.com/attractivechaos/klib/files/4489699/kbtree_itr_test.c.zip)

You say you have tested this on a xilinx spartan 6. How were you able to pass timing? I'm trying on a (admittedly small and lame 7-series artix speed-grade 1...