Add tests for composite models __add__
Merge pull request #129 from tritemio/comp_models_add_tests

Add tests for composite models __add__
FIX: Use asfarray on data and indep vars if needed.
TST: Add a test using None
REF: Organize Fitter file structure.
Merge pull request #130 from danielballan/asfarray

FIX: Use asfarray on data and indep vars if needed.
more doc tweaks
more doc tweaks
remove old wrapping and models
move fitter.py to ui/basefitter.py, update imports
import Fitter from ui in __init__.py
complete move of fitter.py to ui/basefitter.py
Merge branch 'reorg_fitter'