The printing was always only done at the end of osmo_apdu_segment_in(),
so let's leave the decision up to the user if he wants to print the
state at every iteration or not.
We now provide osmo_apdu_dump_context_buf() to the user so he can obtain
a string representation of the internal state for logging at any time he
requires.
Change-Id: Id3e3cf1605dec84077b158c1c5715f8eef2641d5
