prepared statements in embedded library


include/mysql.h:
  stmt_execute 'virtual' method added
include/sql_common.h:
  two functions became global
libmysql/client_settings.h:
  declaration for cli_stmt_execute
libmysql/libmysql.c:
  some functions changed to be usable from embedded library
libmysqld/lib_sql.cc:
  code for embedded stmt_execute added
sql-common/client.c:
  cli_stmt_execute added to the methods table
sql/client_settings.h:
  no need for prepared statements in miniclient