Small improvements at sidebar

While working on the next release (0.6.5) I wanted to improve the sidebar a bit.

• when you hover over an icon you can keep reading info at the top bar, the text won’t disappear unless you move away from the sidebar
• the information at the top bar will show you the build time left if you hover over an item in progress
• the top icons at the sidebar (list icons) are flashing when something interesting happened there
• when icons got added to the sidebar, they will flash briefly

See some of this in action in this short video clip