v0.1.5: Fixed various bugs,

- Make target names and material_ids more flexible by including any iterable
- Fixed target construction issue in MODNet, now expects a list or (n_materials,n_target) nd array
- Fixed evaluation of dataframes in if constructions
- Removed mpids attribute
- Fixed feature_selection .loc error
It is now possible to pass any Iterable for target names and material ids.