Code Cleanup

- Renamed files task.h -> main.h, task.cpp -> main.cpp.  This is to
  prepare for the next rename, which addresses the OpenBSD bug.
- Removed utf8.h, utf8.cpp from Makefile.am, which were inadvertantly
  added.

src/tests/test.cpp

@@ -27,7 +27,7 @@
 #include <iostream>
 #include <iomanip>
 #include <string>
-#include <task.h>
+#include <main.h>
 #include <util.h>
 #include <text.h>
 #include "test.h"