Move "Create new snapshots" button into header
Move "Create new snapshots" button into header

In my previous commit, I moved the accept/reject buttons on the snapshot
page into the header. This commit does a similar thing for the "Create
new snapshots button" on the URL page, which brings a nice bit of
consistency to the app.

Change-Id: Ic5da615a2d7b5a8cf1a7188bbbf3552264731ee2

kalw/diffux,diffux/diffux,kalw/diffux,diffux/diffux,kalw/diffux,diffux/diffux