Add support for '.bf' based cryo games.

[menschel]

Hello,

there are a couple of cryo based games around which use '.bf' format for the game data.

I was wondering if SCUMMVM could support this.

I hacked an unpacker for .bf files last night because there was none to be found.

​https://gitlab.com/Menschel/cryobf

Interesting enough, most of the files content are open source formats, see attached file list.
I don't remember ever reading an Open Source License when playing a cryo game ; .

[menschel]

Just for reference. I have pushed my module to pypi. It can be installed with
"pip install cryobf"