Use QComboBox, QLineEdit and QPlainTextEdit to edit
different option types.
Show changes in the preview without pressing 'Apply' button.
The clangformatchecks.ui file is generated with the python
script that is a part of this commit.
Change-Id: If5ff0acab6edd74f2e087e31fbd3ad1b9f847030
Reviewed-by: Marco Bubke <marco.bubke@qt.io>
