Add Fluid-ish view to AphrontMultiColumnView

Summary: Cleans up some CSS while adding lots of other... Mainly, this allow min-width "tables" that trigger a scroll-bar, but go full width if larger than min.

Test Plan: Tested Workboard Examples and some Project pages, Chrome, Tablet and Mobile Layouts

Reviewers: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D7509

src/applications/project/controller/PhabricatorProjectBoardController.php

@@ -68,7 +68,8 @@ final class PhabricatorProjectBoardController
     }
 
     $board = id(new PHUIWorkboardView())
-      ->setUser($viewer);
+      ->setUser($viewer)
+      ->setFluidishLayout(true);
 
     foreach ($columns as $column) {
       $panel = id(new PHUIWorkpanelView())