Move thread_base.hpp from baseband/ to common/.

I want to use it with M0 code as well.

firmware/common/thread_base.hpp

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __THREAD_BASE_H__
+#define __THREAD_BASE_H__
+
+#include <ch.h>
+
+class ThreadBase {
+public:
+	virtual ~ThreadBase() = default;
+	
+protected:
+	static msg_t fn(void* arg) {
+		auto obj = static_cast<ThreadBase*>(arg);
+		obj->run();
+
+		return 0;
+	}
+
+private:
+	virtual void run() = 0;
+};
+
+#endif/*__THREAD_BASE_H__*/