Fix a bug in manpage.sh and fix the manpages

Whoops. This bug removed the copyright header.
diff --git a/manpage.sh b/manpage.sh
index bc0f5e7..631d162 100755
--- a/manpage.sh
+++ b/manpage.sh
@@ -85,7 +85,7 @@
 	IFS="$_gen_manpage_ifs"
 
 	cat "$manualsdir/header.txt" > "$_gen_manpage_out"
-	cat "$manualsdir/header_${manpage}.txt" > "$_gen_manpage_out"
+	cat "$manualsdir/header_${manpage}.txt" >> "$_gen_manpage_out"
 
 	pandoc -f markdown -t man "$_gen_manpage_md" >> "$_gen_manpage_out"
 }