move gotd fork into repo. (#111)

- update to latest telegram layer
- remove some references to fields in tg.Entities that don't exist in
the schema
- originally added here:
https://github.com/beeper/td/commit/820929062a2ba0104397bc01235ab58a9cff780e
  - referenced here
-
https://github.com/mautrix/telegramgo/commit/124f0967ed195b5a380c9bd02e170ada9710dde3
-
https://github.com/mautrix/telegramgo/commit/4205047aab2e0639217148b5d125bfaab668bd8e

pkg/gotd/bin/bin.go

@@ -0,0 +1,62 @@
+// Package bin implements binary serialization and deserialization for TL,
+// providing Buffer that can decode and encode basic Type Language types.
+//
+// This package is not intended to be used directly.
+//
+// Ref:
+//   - https://core.telegram.org/mtproto/serialize
+//   - https://core.telegram.org/mtproto/TL-abstract-types
+package bin
+
+// Basic TL types.
+const (
+	TypeIntID    = 0xa8509bda // int = Int (0xa8509bda)
+	TypeLongID   = 0x22076cba // long = Long (0x22076cba)
+	TypeDoubleID = 0x2210c154 // double = Double (0x2210c154)
+	TypeStringID = 0xb5286e24 // string = String (0xb5286e24)
+	TypeVector   = 0x1cb5c415 // vector {t:Type} # [ t ] = Vector t
+	TypeBytes    = 0xe937bb82 // bytes#e937bb82 = Bytes
+
+	TypeTrue  = 0x997275b5 // boolTrue#997275b5 = Bool
+	TypeFalse = 0xbc799737 // boolFalse#bc799737 = Bool
+)
+
+// Word represents 4-byte sequence.
+// Values in TL are generally aligned to Word.
+const Word = 4
+
+func nearestPaddedValueLength(l int) int {
+	n := Word * (l / Word)
+	if n < l {
+		n += Word
+	}
+	return n
+}
+
+// Encoder can encode it's binary form to Buffer.
+type Encoder interface {
+	Encode(b *Buffer) error
+}
+
+// Decoder can decode it's binary form from Buffer.
+type Decoder interface {
+	Decode(b *Buffer) error
+}
+
+// BareEncoder can encode it's binary form to Buffer.
+// BareEncoder is like Encoder, but encodes object as bare.
+type BareEncoder interface {
+	EncodeBare(b *Buffer) error
+}
+
+// BareDecoder can decode it's binary form from Buffer.
+// BareEncoder is like Encoder, but decodes object as bare.
+type BareDecoder interface {
+	DecodeBare(b *Buffer) error
+}
+
+// Object wraps Decoder and Encoder interface and represents TL Object.
+type Object interface {
+	Decoder
+	Encoder
+}