Fix for Issue #6197- "Broke Compatibility with Windows XP in Sprint 35"

Fixed [Issue #6197](https://github.com/adobe/brackets/issues/6197)- "Broke Compatibility with Windows XP in Sprint 35"

Code added for Pull Request #383 used function GetFinalPathNameByHandleW() is unavailable on Windows XP.  Changed the call to dynamically call the function with a GetProcAddress() call, but only if it exists in that release of Windows.

Confirmed that Brackets now launches correctly on Windows XP.