Add meaning to dot vote and score poll

Dot vote and score polls now support an optional "meaning" field for each option.

When creating a dot vote or score poll, you can add a short label to each option to explain what a vote for that option represents. For example, a score poll asking members to rate proposals could label each score level: 1 = "Strongly disagree," 3 = "Neutral," 5 = "Strongly agree." The meaning labels appear on the voting form and in results.