新增配置项用于控制是否允许测试数据库版本小于线上数据库

Log: 新增配置项用于控制是否允许测试数据库版本小于线上数据库

  https://github.com/XiaoMi/soar/issues/98

  CREATE TABLE test_id (
    ID int,
    PRIMARY KEY (`ID`)
  )
  SELECT * FROM test_id WHERE id=1;

  fix explain NULL able column bug

  +----+-------------+-------+------------+------+---------------+------+---------+------+------+----------+--------------------------------+
  | id | select_type | table | partitions | type | possible_keys | key  | key_len | ref  | rows | filtered | Extra                          |
  +----+-------------+-------+------------+------+---------------+------+---------+------+------+----------+--------------------------------+
  |  1 | SIMPLE      | NULL  | NULL       | NULL | NULL          | NULL | NULL    | NULL | NULL |     NULL | no matching row in const table |
  +----+-------------+-------+------------+------+---------------+------+---------+------+------+----------+--------------------------------+

  echo "select * from tb" | soar -report-type query-type

  -report-type tables will give SQL affect tables info

	Makefile color code regression
	remove ParseDSN debug log

  SHOW TABLE STATUS

  Rows
  AvgRowLength
  DataLENGTH
  MaxDataLength
  IndexLength
  DataFree

  compatibly with old version(<0.10.0)

  RES.009 not consider about "and", "or"... Operator in
  BinaryOperationExpr

a new config arg 'min-cardinality' for index column selection

  bit type not config as int, when two columns compare will
  give ARG.003 suggestion.

  fix #154, #157 by the way

  compatible with windows file path, regression filepath.Join

  support allow-collates checks

  go test ./... -update

  insert values count large than -max-value-count will give ARG.012

  When set log to console, if fmt.Print larger than 1K
  the output buffer will be truncate. This problem will be
  trigger when set log to stdout, beego and soar both print their
  output into stdout, and this may come into confusing status in
  mac os.

  For fixing this problem, we only allow set log to file not.
  SOAR never write SQL suggest into log. Only developer should be
  concern about log, common user have no need of looking up log.

  chardet will detect input sql charset