New SVG icons from UI team

@cleercode

Not sure about the disabled fill recommendation: opacity worked with any color, unlike this.

Fixes #2478 
This was as per the designers mocks. It does mean that with a moderate amount of tabs, we spend more real estate on whitespace then on content. W/ this change, the top and bottom margins now look out of scale. Land this either way; lets get final tweaks from the designer.