Clean up Project Board Manage / Column Manage pages

Summary: Slightly nicer, more consistent UI. Also removed "Column History" from dropdowns as this is available on the general board manage page.

Test Plan: Review Board and Column management pages.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D17881