- Use Standard method of import
- Try multi workers = 5 to speed up insertion
- Put language in the context while importing
code review
keep compatibility between v7 and v8
Fix class name
Merge remote-tracking branch 'origin/tk_import_standard' into v8

* origin/tk_import_standard:
  Fix class name
  keep compatibility between v7 and v8
  code review
  - Use Standard method of import - Try multi workers = 5 to speed up insertion - Put language in the context while importing