move the spacing from the voting buttons to the session titles

A previous change set the voting button space to be a fixed width so that when placing a vote and the button text changes size causing the button to get wider, the session title doesn't then move around. This causes the edit and delete links that appear on a user's own sessions to have excessive spacing between them and the voting button.

This change puts a margin on the right of the session title instead to achieve the same result without the unwanted side effects.