Bugfixes and improvements

Improved: GenerateCreateTableScriptFromQueryCommand - renamed to
AddCreateTableAsCommand; adds CTAS to a query; includes option to
generate separate CREATE TABLE statement
Bugfix: Code completion crashed when suggested item contains fully
qualified quoted identifiers
Bugfix: OracleTokenReader - invalid resolution of unicode string
literals
Added: OracleStatementSemanticModel - query block columns defined by
single string or number literals have appropriate data types