Minor Tasks fixes

Summary:

• We need to sort Projects explicitly because we go through task-by-task which ruins the ordering. My test case was just small enough not to notice.
• Push "No Project" to the bottom explicitly.
• Simplify/fix the pull of "Unassigned" to the top.
• Fix a return type.

Test Plan: Tested the various sorting cases against a larger test data set.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran, epriestley

Differential Revision: https://secure.phabricator.com/D1988