Pyeee

* Make number of final trajectories an argument instead of a
keyword argument in screening/ee.
* Make number of final trajectories an argument instead of a
keyword argument and sample by default 10*final trajectories in
Morris Method, i.e. morris_sampling.

* Restructured package with functions and utils subpackages.

* Added mention to template of Sebastian Mueller in README.md and
documentation.
* Renamed morris.py to morris_method.py.
* Adjusted names of arguments and keyword arguments in
morris_sampling and elementary_effects to be consistent with
rest of pyeee.

* Split tests in individual files, one per module.
* Changed from ValueError to TypeError if function given to exe
wrappers.
* InputError does not exist, use TypeError in screening.
* Use assertRaises for check error handling in tests.
* Plot diagnostic figures in png files in Morris sampling if
matplotlib installed.
* Coverage at maximum except for eee.py.

* Make systematically function_p versions of all logistic
functions and its derivatives.
* Keep formatting of names and spaces with sub_names_params
functions.
* Close input file before raising error in
standard_parameter_reader_bounds_mask.
* Removed missing coverage in function_wrappers, std_io,
sa_test_functions, and general_functions.

* Tests did not work on TravisCI because pyeee not installed: put
pyeee in PYTHONPATH for tests and in shell script.
* Added tests for standard IO and documented missing coverage.