change value error
update back integration likelihood with hogg's suggestions
overhaul streammodel
redid model parameters
TODO: add test - skeleton here
don't import parameter
move MPI import
added a sampler for stream model
add hacks for parameter to pickle and unpickle
move mpi import
remove extraneous function
specify number of particles when reading hdf5
rebuilding with new framework
num particles
make model and read potential
add magic to load yaml as ordered dict
subset of tub
add parameters to model as necessary
added a test
model uses true position if not modeling parameter