Merge pull request #279 in ZP/z-push from feature/ZP-965-allow-to-extend-sqlstatemaschine-and-table-prefix to develop

* commit '15ef4d5c':
  ZP-965 Use placeholders for table names in statements for table creation. Add curly braces around $this->table_name in SQL statements.
  ZP-965 Allow to extend SqlStateMachine and set a table-prefix.