R1:70a5ec600d26

Allowing Closing of questions

Summary:
Fixes T3579

As a basic overview, this enables the author of a question to open/close a question.

Other bits;

- Add "Open" filter to the builtin queries
- Add "Status" to search form
- Refactor ponder constants
- Add coloured bars for different question statuses

Test Plan:
- Open/Close questions
- Search for some bits
- Use filters

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T3579

Differential Revision: https://secure.