remove internal packages, move everything into q3rcon

{request}.buf initialised with 0 length.

encoder, decoder interfaces added.

response.go

@@ -0,0 +1,21 @@
+package q3rcon
+
+import "bytes"
+
+const (
+	responseHeader = "\xff\xff\xff\xffprint\n"
+)
+
+type response struct{}
+
+func newResponse() response {
+	return response{}
+}
+
+func (r response) IsValid(buf []byte) bool {
+	return len(buf) > len(responseHeader) && bytes.HasPrefix(buf, []byte(responseHeader))
+}
+
+func (r response) Decode(buf []byte) string {
+	return string(buf[len(responseHeader):])
+}