Start of MD5 Checks. Introduction of md5.exe

Added MD5 for both versions of KF2 OS's offered.
[TODO] Add MD5 checks for KFHD7 and KFHD8.9
[TODO] Add Doublecheck of MD5 AFTER download, currently used to check existing file
[TODO] Add back bootloader menu access once code overhauled for reliability

Signed-off-by: David Long <david.long@canonicaldev.com>