Updated Invoke-ReflectivePEInjection for Win8.1

Needed to make minor changes to the marshal code due to a backwards
compatibility breaking update made to .net 4.5.
Updated Invoke-NinjaCopy for Windows 8.1

.net 4.5 introduced breaking changes to several marshalling functions.
Added fixes.
Added version, minor tweaks to NinjaCopy.

Added version to NinjaCopy and ReflectivePEInjection.
Added Convert-FileToBase64String to get base64 versions of PE files.
Adding Invoke-Mimikatz