Caf bugfix

The Caf interpreter test was not actually testing the new
Number=R caf field.  Updated the tests to actually test this,which
broke.  Fixed how we were calling info_for_allele to return the
expected value.
Agreed. Perhaps you could use the 4x2, 4x1 naming convention instead?

Though to be honest 4x2 and 4x1 confused me for a bit too, because I thought... 'four by two?' And then I noticed it corresponded to the versions.