fixed problem with kb_itr_get always returns iterator same as kb_itr_first

[tsanyen]

as kb_itr_get always returns an iterator from first;

[till-s]

Your proposed fix is incomplete. A correct solution is already in PR #73.

I created an issue (#141) for this bug with a test program that fails with this PR (but passes with PR73 provided that the kb_itr_get() is modified to use kb_itr_getp() which is introduced by PR#73)