Pull Request to merge changes related to Cross Platform Path Normalization

Hello this is SoujiSeta again. I was wondering could you merge in some more changes to make PKHex more portable.

I added a NormalizePath function that will take a string and return a canonical path that will work on the operating system that the application is running on.
So on Windows it will return a fully qualified Windows path and on Linux and Max it will return qualified unix path.

I also changed all but one of the hard coded "\\" windows path separator to use the Path class Path.DirectorySeparatorChar to improve portability.

I have tested the changes both on a Windows 7 VM and on ArchLinux to make sure that it they do work.

Thank you,
SoujiSeta