Bug 497924 - [Welcome] Solstice should trigger generation of doctype so as to guide IE

  - Add support for marking a theme as HTML5 via the standardSupport property
  - Use HTML5 property to add an HTML5 doctype
  - When in HTML5 and on IE, add a X-UA-Compatible IE=edge meta element
    to disable IE's 'compat view'

Change-Id: Icb75e8384adc0afa2ae5e334f5bcd91496c57cba
4 files changed