Bump version to 0.1.2-SNAPSHOT

Signed-off-by: Gergely Nagy <algernon@balabit.hu>
codec: Use :keys-based destructuring

To make the code a little bit easier to read, use :keys-based
destructuring for optional decode-frame arguments. So instead of
(decode-frame buffer :type param1 param2), we will have:

(decode-frame buffer :type :key1 param1
                           :key2 param2)

Which is easier to understand without looking at the source or
documentation of the multi-method.

Signed-off-by: Gergely Nagy <algernon@balabit.hu>
Merge branch 'feature/code-cleanup/decode-frame-optmap'