Add leading comma option to sql formatter & bug fixes & some enhancements (#1087)
* Some memory improvments in StringHelper
* Set current culture to InvariantCulture in test-dependent culture
* Fix PostgreSqlFormatter adding extra space #623
* Fixes #677
* Add leading comma sql formatter option #712
* Prevent calling ToString when appending token in sql formatter
* Optimize Compress/Decompress GZip data