Redesign PonderQuestionView

Summary: Full new UI, testing some upcoming treatments for consideration in other View controllers. Small tweaks to allow PHUITwoColumnView to have fixed and fluid width, and let TransactionCommentView go fullWidth.

Test Plan:
Tested a number of Ponder cases, New Question, with and without summary, with and without answers, with and without comments. Mobile, Tablet, and Desktop layouts. Verify Project and Profile UI's still in tact.

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Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D15315