deps: Update msgpack

The new version fixes serialization/deserialization of EXT 8/16/32
runtime: Fix one of python sanity checks

Use sys.stdout.write which is compatible with python 2 and 3
msgpack-gen: Fix msgpack_rpc_init_function_metadata

The function was broken on release builds
deps: Switch lua msgpack library to one that supports 2.0
channel: Fix unpacker loop condition
Merge PR #1185 'Some fixes and missing changes'