Added resumable loading, along with signal handling.

This version can store state after receiving SIGINT.
This is achieved by polling FIFO read state;

Channel.cpp

@@ -0,0 +1,42 @@
+#include "Channel.hpp"
+#include <stdexcept>
+#include "u2f.hpp"
+#include "U2F_CMD.hpp"
+#include <iostream>
+
+using namespace std;
+
+Channel::Channel(const uint32_t channelID)
+	: cid{ channelID }, initState{ ChannelInitState::Unitialised }, lockedState{ ChannelLockedState::Unlocked }
+{}
+
+uint32_t Channel::getCID() const
+{
+	return cid;
+}
+
+void Channel::handle(const shared_ptr<U2FMessage> uMsg)
+{
+	if (uMsg->cmd == U2FHID_INIT)
+		this->initState = ChannelInitState::Initialised;
+	else if (uMsg->cid != this->cid)
+		throw runtime_error{ "CID of request invalid for this channel" };
+
+	if (this->initState != ChannelInitState::Initialised)
+		throw runtime_error{ "Channel in incorrect (uninitialized) state to handle request" };
+	else if (this->lockedState != ChannelLockedState::Unlocked)
+		throw runtime_error{ "Channel in incorrect (locked) state to handle request" };
+
+	clog << "Handling uMsg with CMD: " << static_cast<uint32_t>(uMsg->cmd) << endl;
+	return U2F_CMD::get(uMsg)->respond(this->cid);
+}
+
+void Channel::init(const ChannelInitState newInitState)
+{
+	this->initState = newInitState;
+}
+
+void Channel::lock(const ChannelLockedState newLockedState)
+{
+	this->lockedState = newLockedState;
+}