In the vast majority of cases, people want poll voters to be public. Previously, the checkbox for this was hidden behind the 'show advanced' settings in the poll builder UI.
This commit makes three changes to improve the experience:
1. Add `public=true|false` to poll markup (previously it would only be added when true
2. Bring the 'public' switch outside the 'show advanced' section for improved visibility
3. Change the default to 'true'
1. recent css regression related to modal upgrade
2. autofocus and on-enter regressions
3. array related linting issue (reliance on Ember's firstObject/lastObject)
Adds an optional title attribute to polls. The rationale for this addition is that polls themselves didn't contain context/question and relied on post body to explain them. That context wasn't always obvious (e.g. when there are multiple polls in a single post) or available (e.g. when you display the poll breakdown - you see the answers, but not the question)
As a side note, here's a word on how the poll plugin works:
> We have a markdown poll renderer, which we use in the builder UI and the composer preview, but… when you submit a post, raw markdown is cooked into html (twice), then we extract data from the generated html and save it to the database. When it's render time, we first display the cooked html poll, and then extract some data from that html, get the data from the post's JSON (and identify that poll using the extracted html stuff) to then render the poll using widgets and the JSON data.
