v2.9

• Updated cpp-driver to 2.7.0
• Updated lager to 3.4.2
• Fix for segmentation fault when we try to bind more arguments than we specified (#14).
• API breaking changes:
  • non prepared statements are executed now using query/1, query_async/1 and query_new_statement/1 (used when should run inside a batch)
  • the following methods are removed: async_execute_statement/1, async_execute_statement/3, execute_statement/1
  • removed support for binding non prepared statements.
• Add support for user-defined type (UDT): decode as proplist.
• Major code refactoring in the way the nif terms are bind in native cass statements