R1:65cf34e2b81c

Add UI elements for sortable tables

Summary: Allow AphrontTableView to render with sort indicators and links in its columns.

Test Plan: Looked at UI example.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran, epriestley, sandra

Maniphest Tasks: T994

Differential Revision: https://secure.phabricator.com/D1946