changed nativepath to support bindings

When binding files to views in XAML, such as image urls to be image source parameter, Windows store apps can only read urls that use "ms-appdata:///local/" instead of the absolute local path. using "ms-appdata:///local/" works fine in all other file read/write cases across the board for Windows.

How have people been dealing with this problem so far? Another solutions is to create a converter for the binding, but this seems much more elegant and would give delight to new users to see path bindings work out of the box