Coding standards to follow when writing code in the Macaulay2 engine

1. Run your c++ code through clang-format as in:

   find Macaulay2/e -name \*.cpp -o -name \*.hpp | xargs clang-format-3.8 -i -style=file

   or, more simply, in the e directory (or subdirectories), run, on e.g. foo.hpp, foo.cpp:

   clang-format-3.8 -i -style=file foo.hpp
   clang-format-3.8 -i -style=file foo.cpp

   The .clang-format file is in the top level M2 directory.

   In particular, no tabs in these files.
   
2. Header file placement.

   See

       https://google.github.io/styleguide/cppguide.html#Names_and_Order_of_Includes

