Fix refcounting in object

This commit also fixes unref().
Previously, we had a lock for refcounting but didn't use it _at all_.
This commit introduces proper recount-locking and thus fixes a _lot_ of
potential issues.
Add log when initializing deserializer
Add log when initializing deserializer internal state
Add logs to deserialize callback
Add log context for deserializer callbacks
Add log for logging what gets parsed atm
Add explanation logs for yajl_null_cb()
Add explanation logs for yajl_boolean_cb()
Add explanation logs for yajl_integer_cb()
Add explanation logs for yajl_string_cb()
Add explanation logs for yajl_start_map_cb()
Add explanation logs for yajl_map_key_cb()
Added failure logging, fixed state transition
Add explanation logs for yajl_end_map_cb()
Add explanation logs for yajl_start_array_cb()
Add explanation logs for yajl_end_array_cb()
Add logging for transaction setup
Add logging for message finalization
Merge pull request #500 from matthiasbeyer/add-deserializer_logs

Add logging for JSON deserializer
Merge pull request #497 from neithernut/fix-refcount_locking

Fix refcounting in object