mysql_upgrade should not call other applications by command line (as it makes password being visible).

This tool was refactored to call mysql queries by MYSQL C API. To use mysqlcheck it was first divided into library and client that parses options, creates connection and passes parsed parameters to library. Mysql_upgrade uses this mysqlcheck library. Also C++ wrappers were created on parsing options to encapsulate program options groups. Classes for common groups of options were implemented on that. Abstract client tool program class was implemented. All this new functionalities were used in mysql_upgrade. A C++ wrapper to mysqlcheck functionality was created and used in mysql_upgrade.