generalization of mtr to support suite.pm extensions:

* no automatic --loose-skip-innodb added by mtr based on the test name.
  instead loose-skip-innodb is now in the default_mysqld.cnf
* have_innodb_plugin.inc is changed to give a verbose "skip" message
  (instead of "require: true")
* My::Suite class. It's support in mtr, and everywhere
* support for suite.pm
* when sorting tests, take combinations into account
* support for SUITENAME_COMBINATIONS
* no special treatment for innodb_plugin in mtr_cases.pm
* two special pre-created config groups: ENV and OPT
* allow option names to start from #
* allow magic option to have an argument
* remove dead code
* fix @-substitution to works as expected
* new processes take the value of $opt_verbose automatically, no need to pass it to a constructor
* innodb_plugin suite uses suite.pm and combinations file to test as much as possible
  (innodb plugin, xtradb plugin, xtradb static - whatever available)
* besides test-master.opt and test-slave.opt a test.opt file is also
  loaded, both for master and slave
* .opt files for all included files are loaded too
* progress report in the xterm titlebar

mysql-test/include/have_innodb_plugin.inc

@@ -1,4 +1,5 @@
-disable_query_log;
---require r/true.require
-SELECT (plugin_library LIKE 'ha_innodb_plugin%' OR plugin_description LIKE '%xtradb%') AS `TRUE` FROM information_schema.plugins WHERE LOWER(plugin_name) = 'innodb' AND LOWER(plugin_status) = 'active';
-enable_query_log;
+if (!`SELECT COUNT(*) FROM INFORMATION_SCHEMA.PLUGINS
+         WHERE PLUGIN_NAME = 'innodb' AND PLUGIN_STATUS = 'active' AND
+              (PLUGIN_LIBRARY LIKE 'ha_innodb_plugin%' OR PLUGIN_DESCRIPTION LIKE '%xtradb%')`) {
+  skip Need InnoDB plugin or XtraDB;
+}