v1.3.1

• Update the document and examples.
• Use Go 1.17.
• Tweak golangci-lint in CI.

v1.3.0

• Avoid bit-shifting in Buffer.Clone().
• Add Builder.WriteBits() method.
• Add Buffer.Uint*() and Buffer.PutUint*() methods.

v1.2.0

• Add functions and methods to copy bits from/into Buffer.
• Add an offset to Buffer data structure to avoid unnecessary bit-shifting.
• Add Buffer.Slice() methods.
• Add NewBufferFromByteSlice() that can handle []byte as a bit array without copying it.
• Add other trivial methods.