Removed unused includes in model_header.hpp (appled fixme) and added some lines to .gitignore (files generated by RStan make)
avoid integer division in tests

These two tests created an array of doubles where elements are
N / K where both N and K are integers, which is a "narrowing"
error under the C++11 standard. K is now changed to a double.
Merge pull request #60 from stan-dev/feature/stop_narrowing

avoid integer division in tests
Merge pull request #57 from randommm/feature/matrix_organization

Removed unused includes in model_header.hpp
Merge branch 'develop' into feature/reduce_warnings