Microsoft has updated their popular extensions pack Productivity Power Tools for Visual Studio 2013. One interesting new feature they have added is Solution Explorer Errors. It shows error, warning, and message squiggles in the Solution Explorer window and hovering over a squiggle displays a popup filtered to the selected file or project with the ability to go to the corresponding problematic file line:

Solution Explorer Errors in Visual Studio 2013

See 10 minutes video describing all 11 new features. Read detailed breakdown for all features and download the tools.