Correct errorHandler placement in doc

In the migrating-4 page, errorHandler was placed before the routes, this was confusing.
fontawesome
Merge branch 'aenario-patch-1' into gh-pages
error handling fixed
Merge branch 'gh-pages' into menu
Merge branch 'menu' into mobile
mobile menu
removed octicons
padding right on mobile view
overlay
click outside to close the mobile menu
mobile menu scroll
line height
top padding of inner pages
content fix
Merge branch 'menu' of github.com:strongloop/expressjs.com into menu
Merge branch 'menu' of github.com:strongloop/expressjs.com into menu
merged rand's work with mobile banch
modularized header content
deleted redundant images and added footer images