Added msg_pprint() + Fixed double free() in unpack_item()

Added msg_pprint(message_t * msg, int depth)
Fixed potential double free() in unpack_item()
Added .idea directory to .gitignore (clion/pycharm)
Improved ctlv.py

Added proper ArgParse options (pack, unpack)
pack/unpack actions now work with json(!) files/objects
Fixed Message().pack() (now supports lists too)
Moved back to a type(dict) as base for Message
Handling "lists" properly now