Added variation with alpha-channel and a little fix

Just like with the 8bit-editions of KotatsuBFX2014 and Simple, this pack now has a version that features alpha-channel instead of background-color, too.

Also, in the original 8bit-variation with background, attack #D13 had graphical glitches in the version inside "High" folder, this is fixed now when you redownload it.

～炬燵あ