Update and rename list.php to button-block.php

This file displays the buttons as a bootstrap btn-block. The buttons are stacked and have the same width. As the button text can be longer than one line which looks not very nice, the style aligns the text left rather than center und creates a right and left  padding.
Merge pull request #24 from knulli/patch-1

Update and rename list.php to button-block.php