prepared statements in embedded library.
some fixes after testing


include/mysql.h:
  virtual method added
libmysql/client_settings.h:
  declaration added
libmysql/libmysql.c:
  implementation added
  mysql_fetch changed to work in both libraries
libmysqld/lib_sql.cc:
  implementation added
sql-common/client.c:
  added items in methods table
sql/client_settings.h:
  decided to remove such defines - i placed single #ifdef in client.c