More debugging functionality (FlatBuffers + RT)

[pablohoch]

FlatBuffers

Convert any FlatBuffers table or struct to JSON (not just Message or root types):

#include "motis/module/message.h"
using namespace motis::module;

Station const* table = ...
std::string json = fbs_table_to_json(table, "motis.Station");
std::string single_line_json = fbs_table_to_json(table, "motis.Station", json_format::SINGLE_LINE);

JSON trip ids:

#include "motis/core/debug/fbs.h"

schedule const& sched = ...
trip const* trp = ...
std::string json = debug::to_fbs_json(sched, trp);

RIS & RT

• motis.ris.Message renamed to motis.ris.RISMessage (naming conflict because namespaces are ignored in some places in FlatBuffers related code, e.g. motis_copy_table)
• Also renamed motis.ris.MessageUnion -> motis.ris.RISMessageUnion and motis.ris.MessageHolder -> motis.ris.RISMessageHolder for consistency
• Added an optional message history feature for debugging RT updates
  • Enabled using the config option rt.history = 1 (disabled by default)
  • All received messages for a trip can be retrieved using the new /rt/message_history API (in RISMessage format)

RSL

• Some check + debugging improvements