update bcrham tests for 1-f f/3 insert emissiosn
remove pair emission specification from cpg example

Now we've got k-hmms, we're moving away from specifying pair hmms as a
table, and instead specifying as single emissions (which then get
multiplied together properly during dp table calculation).

Note that this means no joint emission at the moment, although it's be
easy to turn on later.
switch to cleaner k-hmm emission calculation

Now we take the single emission for each sequence and multiply them
together.

NOTE this means we're ignoring any pair emissions that were
specified (if you're pair emissions weren't joint, the result will be identical)
remove superfluous n_seqs_per_track
remove superfluous pair argument to bcrham

already specified implicitly in csv input file