Merge branch 'dev'

* dev:
  docs typo
  ready for 0.3.5
  anthor delete, create
  sample codes typofixed
  another snip of sample code
  use tuple result with MySQLdb
  typofixed
  remove useless spaces when generating sql
  typo
Merge branch 'dev'

* dev:
  ready for 0.3.6
  doc for distinct
  changes for v0.3.6
  tests for distinct; models.having
  docs for `having` and `groupby`
  add distinct keyword
  tests for having; changes for v0.3.6
  add having
  changes for 0.3.6
  add groupby to models; add its tests
  add test for models.groupby
  add group by
  Database.change and Database.select_db
  add `Database.change`
typofixed;
rewrite curd.py typo