Addresses https://github.com/JamesPHoughton/pysd/issues/80

[JoonaTuovinen]

Added warning to set_components when used with stocks
(just warning because it is actually an easy way to analyse models by overriding stock values to constants)
Added test_set_components_warnings
Moved the test_py_model_file and test_mdl_file under class TestPySD

[coveralls]

Coverage increased (+0.03%) to 94.318% when pulling ca854e6 on JoonaTuovinen:master into 2b05895 on JamesPHoughton:master.

[JamesPHoughton]

This looks great - I think the travis build error is due to the way the model file reference is generated here: https://github.com/JoonaTuovinen/pysd/blob/2421af710744e19501d4d3cfee718ebcd667ae0b/pysd/pysd.py#L125

I'm guessing that the test used the .pyc file instead of .py, and the replace function left the trailing 'c'. I suppose a more robust way to do this would be to have the parser save the original filename directly. Not sure what that would require though...

[JamesPHoughton]

@JoonaTuovinen would you mind also having a look at this: #79 - its closely related to what you're doing here, and would be good to patch together.

I think you can leave the PR open, and then when you make changes to your copy, it'll update the PR with them appropriately...

[JoonaTuovinen]

@JamesPHoughton Yes you're right, more robust for getting the mdl_file would be using the original mdl filename directly. Should I just save it inside the generated .py file?

I think it still makes sense to get the py file by str(self.components.file).replace('.pyc', '.py'). Seems over engineering to save the py file name.

I'll do the #79 too.

I wonder why, when I run the test it doesn't use the compiled file and the test passes.

[JamesPHoughton]

Actually, do we need the original model file name as a variable? The .py filename is helpful because you may want to load the translated version and skip the work of translating a second time, and so its helpful to have programmatic access to that name.

We might be ok for the original file name just listing it in a docstring at the top of the file. Then if someone opens the translated file they know where it came from.

[JamesPHoughton]

Updated this PR to reflect changes in stateful representation of stocks, etc in #101

@JoonaTuovinen does this work for you?