[SciPy-dev] Some tests for function_base.py

Hello, Since I was trying to fix the unwrap function I decided to add some more tests to the function_base.py In the process I've also suggest some corrections to the code: unwrap: was failing by using the old typecode histogram: one variable was cleaning the input data histogram: the bin generation was not adequate creating unbalanced bin counts. I've cross checked with matplotlib code (both are very similar) and corrected the histogram functions. Hope this will be usefull. Hugo Gamboa