Improved error handling

Fixes a memory leak and avoids aggressive busy looping when problems
accessing tty device.

src/main.c

@@ -21,9 +21,12 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
 #include "tio/options.h"
 #include "tio/tty.h"
 #include "tio/log.h"
+#include "tio/error.h"
+#include "tio/print.h"
 
 int main(int argc, char *argv[])
 {
@@ -35,6 +38,9 @@ int main(int argc, char *argv[])
     /* Configure output terminal */
     configure_stdout();
 
+    /* Install error exit handler */
+    atexit(&error_exit);
+
     /* Install log exit handler */
     atexit(&log_exit);