Update API according to the update in November 2020

Update applogger.go

Add AlgoOrderClient and examples

Fix latest trade return value type

Feature: Replace console output to AppLogger, and updated according t…

…o API update in April 2020

Style: Fix README code indent and contents

Update README.md

Update README.md

Refine the document after using go modules:
1. Remove useless install section
2. Simplify the quick start section
3. Refine Usage section