add FAQ and  add mysql environment verbose info

fix #184 and #173

  SHOW TABLE STATUS

  Rows
  AvgRowLength
  DataLENGTH
  MaxDataLength
  IndexLength
  DataFree

  change encoding/json -> github.com/CorgiMan/json2

Solve the function of duplication

  WHERE col = col = '' and col1 = 'xx'

* import bats for cli test

  https://github.com/sstephenson/bats

* add simple test case for cli use bats

* format main.bats add env

* replace main_test.sh with main.bats

  make explain suggestion sorted
  make index suggestion sorted

* add test database world_x

* update bats golden result

* make docker add 180s timeout

  1. add timeout for docker start
  2. add not explain able sql test case into explain_test.go

* explain info Using index VS Using index condition

  remove nonappearence key from explain extra info

* add timeout for test

* fix #178  JSON datatype only support utf8mb4 now

* splitstatement support optimizer hint

  https://dev.mysql.com/doc/refman/8.0/en/optimizer-hints.html
  https://dev.mysql.com/doc/refman/8.0/en/comments.html

* vendor daily update

* format explain suggestion content

  1. update vendor
  2. `use db` can't be explain, it will print err log at explain.go

* fix #176

  JSON datatype only support utf8mb4 now

* splitstatement support optimizer hint

  https://dev.mysql.com/doc/refman/8.0/en/optimizer-hints.html
  https://dev.mysql.com/doc/refman/8.0/en/comments.html

* vendor daily update

  https://dev.mysql.com/doc/refman/8.0/en/optimizer-hints.html
  https://dev.mysql.com/doc/refman/8.0/en/comments.html

  JSON datatype only support utf8mb4 now

  single table select * don't auto-complete table name
  multi table select tb1.*, tb2.* auto-complete table name

  compatibly with old version(<0.10.0)