- Ported addPrimaryKey and created dropConstraint. - The dropConstraint method can be used both for dropPrimaryKey and dropForeignKey
Replaced dropConstraint with dropPrimarykey method.
- Added drop/add primary key methods to Command.php - Added drop/add primary key methods to QueryBuilder.php - Added mysql specific dropPrimarykey method - Added sqlite specific dropPrimarykey and addPrimaryKey methods - Added uint testing for dropPrimarykey and addPrimaryKey methods - Corrected postgresql column types, by adding length and precision
Updated code styling and added braces.
Merge pull request #519 from gevik/issue-466

Issue 466 (add/drop PrimaryKeys)
Minor coding style fix.