Feature/mwacomp

@seananderson can you check the following and then bring it into feature/data. I added calls within the package to integrate ```sample_mwacomp``` (a new function). ```sample_mwacomp``` is basically a copy of ```sample_mlacomp``` with a few simple changes. I am not sure if there is a better way to do this, like have a single function that is called by two functions? Also I did not document the function. I forgot until right now, so there is no associated rd file. Sorry about that.
@colemonnahan and @taylori, can you check the actual function ```sample_mwacomp```. I am not sure where the CV should come from in the sampling. Right now the function uses the same CV that ```sample_mlacomp``` uses.