Change header z-index
Change header z-index

This increases the z-index of the headers from 1 to 2. The reason
is that Ace Editor's selected row has a z-inde of 1 and the API
URL bar is being incorrectly overlapped.

michellephung/couchdb-fauxton,robertkowalski/couchdb-fauxton,michellephung/couchdb-fauxton,popojargo/couchdb-fauxton,apache/couchdb-fauxton,robertkowalski/couchdb-fauxton,cloudant/couchdb-fauxton,benkeen/couchdb-fauxton,apache/couchdb-fauxton,cloudant/couchdb-fauxton,popojargo/couchdb-fauxton,benkeen/couchdb-fauxton,michellephung/couchdb-fauxton,garrensmith/couchdb-fauxton,robertkowalski/couchdb-fauxton,cloudant/couchdb-fauxton,garrensmith/couchdb-fauxton,michellephung/couchdb-fauxton,popojargo/couchdb-fauxton,robertkowalski/couchdb-fauxton,michellephung/couchdb-fauxton,garrensmith/couchdb-fauxton,apache/couchdb-fauxton,apache/couchdb-fauxton,cloudant/couchdb-fauxton,popojargo/couchdb-fauxton,benkeen/couchdb-fauxton,garrensmith/couchdb-fauxton