2. dialog plugin now always returns mysql->password if non-empty and the first question is of password type
3. split get_tty_password into get_tty_password_buff and strdup.
4. dialog plugin now uses get_tty_password by default
5. dialog.test
6. moved small tests of individual plugins into a dedicated suite
bugfix: garbage in PLUGIN_VAR_STR variables when INSTALL'ing a plugin
mysql-test/include/default_mysqld.cnf:
disable feedback plugin by default.
when enabled - tag is as a test run