remove internal packages, move everything into q3rcon

{request}.buf initialised with 0 length.

encoder, decoder interfaces added.

request.go

@@ -0,0 +1,35 @@
+package q3rcon
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+)
+
+const (
+	bufSz         = 1024
+	requestHeader = "\xff\xff\xff\xffrcon"
+)
+
+type request struct {
+	password string
+	buf      *bytes.Buffer
+}
+
+func newRequest(password string) request {
+	return request{
+		password: password,
+		buf:      bytes.NewBuffer(make([]byte, 0, bufSz)),
+	}
+}
+
+func (r request) Encode(cmd string) ([]byte, error) {
+	if cmd == "" {
+		return nil, errors.New("command cannot be empty")
+	}
+
+	r.buf.Reset()
+	r.buf.WriteString(requestHeader)
+	r.buf.WriteString(fmt.Sprintf(" %s %s", r.password, cmd))
+	return r.buf.Bytes(), nil
+}