.NET classic and portable platform split

It has beem spotted that rather than changing the original project from a classic .NET class library to a portable class library, a second project targetting a portable class library should have been create and simply link to the original project source file.

So here I created a second project so we can now output 2 libraries, one targetting at .NET classic platform and the other one at the PCL compatible platforms. This will make it less of a hassle for people targetting at .NET classic platform.