UC2 compatibility

To my knowledge, newer version (to v10.00) of Total Commander can still using UC2 packer to unpack .uc2 file. Only the "pack" function is disabled in x64 environment.

To make UC2 (unpacking files) working under x64 environment, I use a utility called MS-DOS Player which can be obtained from http://takeda-toshiya.my.coocan.jp/msdos/index.html