Add fixed roll files to package

[skent259]

I can see several ways in which having fixed roll files could be useful:

• Small roll files used for testing, to snapshot the results of a strategy
• After incorporating a simulation module (see Add methods for running simulations #14), users could test strategies against some standard roll files
• For users who don't believe in the randomness of some computers. Other craps software offer rolls with different randomization schemes, e.g. Wincraps https://cloudcitysoftware.com/brfiles.htm.