Add ai-battle cli

[wichern]

Adds an optional binary that runs headless (no UI) AI battles.
This can be useful when creating training data or testing new AIs.

I'm not sure if this is placed correctly or whether it should even be part of the master branch.
In any case, I would like your feedback on this tool. It aims to reuse as much of s25main as possible in order to create accurate replays.

[Flamefire]

Few remarks to fix compilation

This will likely glitch on Windows though:

   `printf("\x1b[%dA", 8 + world_.GetNumPlayers()); // Move cursor back up`

[Flamefire]

Suggested change

	unsigned random_init = std::chrono::high_resolution_clock::now().time_since_epoch().count();
	auto random_init = static_cast<unsigned>(std::chrono::high_resolution_clock::now().time_since_epoch().count());

[Flamefire]

Suggested change

	printf("Replay written to %s\n", canonical(replayPath_).c_str());
	bnw::cout << "Replay written to " << canonical(replayPath_) << '\n';

[Flamefire]

Suggested change

	printf("Savegame written to %s\n", canonical(path).c_str());
	bnw::cout << "Savegame written to " << canonical(path) << '\n';

[Flamefire]

Suggested change

	#include <boost/nowide/iostream.hpp>
	#include <boost/nowide/filesystem.hpp>
	#include <boost/nowide/iostream.hpp>

[Flamefire]

Suggested change

	bnw::args _(argc, argv);
	bnw::nowide_filesystem();
	bnw::args _(argc, argv);

[Flamefire]

Suggested change

	#include <boost/nowide/iostream.hpp>
	#include <chrono>
	#include <sstream>
	std::vector<PlayerInfo> GeneratePlayerInfo(const std::vector<AI::Info>& ais);
	std::string ToString(const std::chrono::milliseconds& time);
	std::string HumanReadableNumber(unsigned num);
	namespace bfs = bfs;
	using bfs::canonical;
	#include <boost/nowide/iostream.hpp>
	#include <chrono>
	#include <sstream>
	std::vector<PlayerInfo> GeneratePlayerInfo(const std::vector<AI::Info>& ais);
	std::string ToString(const std::chrono::milliseconds& time);
	std::string HumanReadableNumber(unsigned num);
	namespace bfs = boost::filesystem;
	namespace bnw = boost::nowide;
	using bfs::canonical;