a) Never. Microsoft has no intention of ever supporting anything but WEC 2013 (and later if they exist) in the newer versions of Visual Studio (2012 and beyond). For WEC7 your option is, and will remain Studio 2008.
b) WEC7 is not supported now is Studio 2012, so there's no "still" to be continued.
So what that means is that for development you use:
CE 6.0R3 --> Studio 2008
WEC 7 --> Studio 2008
WEC 2013 --> Studio 2012