Always re-setup in development, upgrade brunch modules.

Since code is constantly changing in development, it make more sense
to always reload some service in case of development than only on
the first link.
Fix broken slow animation in iOS 7 and Mavericks.

Switch to use position: absolute for navbar so that expanding
nav bar no longer triggers full page redraw, which is extremely
slow in Safari in iOS 7 and Mavericks.