Resolve PanelPluginTest::testConvertMethodExists

remain failure tests

* PanelPluginTest::testParameterNoHeading

* PanelPluginTest::testParameterWithHeading

* PanelPluginTest::testHeadingParse
Resolve PanelPluginTest::testParameterNoHeading

remain failure tests

* PanelPluginTest::testParameterWithHeading

* PanelPluginTest::testHeadingParse
Add parser to input string by user in panel plugin
Fix test to use double quotation marks insted of single
Resolve PanelPluginTest::testParameterWithHeading

remain failure test

* PanelPluginTest::testHeadingParse
Fix typo

* line127: h1 => h6
Fix tests to use parsing right
Resolve PanelPluginTest::testHeadingParse

Use preg_match() & preg_replace to flexible parsing.