Fix errors and mistakes on 11.sql.

* Add missed semicolons.
* Remove the inappropriate trailing whitespace in 'Language ' value.
* Drop constraints and columns if only they exists.
* Drop constraints before drop related columns
* To avoid unique constraint violation for the name field,
    * Delete duplicated rows.
    * Prepend category to name.
Merge pull request #63 from npcode/fix/11.sql

Fix errors and mistakes on 11.sql.