Rewrite implementation in TypeScript

[gfx]

Completely re-written the implementation in TypeScript based on the original (@uupaa san's), including lots of bug fixes and performance improvement.

• covers https://github.com/kawanet/msgpack-test-js
  • binary
  • timestamp extension
  • BigInt not in this PR
• packaging tasks
• FIx performance issues on NodeJS v12
  • 2d0b989 It's because TextEncoder is introduced but slower than pure JavaScript impl

Test Coverage

as of 950e05a

=============================== Coverage summary ===============================
Statements   : 92.05% ( 382/415 )
Branches     : 88.24% ( 45/51 )
Functions    : 95.74% ( 45/47 )
Lines        : 91.77% ( 368/401 )
================================================================================

Benchmark compared to msgpack-lite

Benchmark on NodeJS/v12.1.0

operation	op	ms	op/s
buf = Buffer.from(JSON.stringify(obj));	509600	5001	101899
buf = JSON.stringify(obj);	837700	5000	167540
obj = JSON.parse(buf);	346700	5001	69326
buf = require("msgpack-lite").encode(obj);	353000	5000	70600
obj = require("msgpack-lite").decode(buf);	272500	5000	54500
buf = require("@msgpack/msgpack").encode(obj);	368800	5001	73745
buf = Buffer.from(require("@msgpack/msgpack").encode(obj));	353100	5001	70605
obj = require("@msgpack/msgpack").decode(buf);	287500	5001	57488