Added my examples
Addressed comments from PTF
Updated .gitignore
Forgot to include boost_python_headers.hpp from numpy_eigen
Forgot docstring for member a
Corrected spelling mistakes

* Corrected minor spelling mistakes

* Added stream operator example
Fix bug in python string method wrapper

- this was just a typo from before
Merge pull request #1 from ethz-asl/feature/python_exports

Added my examples