Removed obsolete coord to bytes transformation. Added TODO.

TODO

@@ -0,0 +1,2 @@
+- Check if the mutex stuff in the LevelDB is really needed.
+  LevelDB has some threadi-safety already.

coords.go

@@ -6,16 +6,6 @@ package main
 
 import "strconv"
 
-// Returns database pos as a byte slice.
-func pos2bytes(pos int64) []byte {
-	buf := make([]byte, 8, 8)
-	for i := 7; i >= 0; i-- {
-		buf[i] = byte(pos & 0xff)
-		pos >>= 8
-	}
-	return buf
-}
-
 // Constructs a database key out of byte slice.
 func bytes2pos(key []byte) (pos int64, err error) {
 	return strconv.ParseInt(string(key), 10, 64)