Log Message:
Update to 0.37

Upstream changes:
0.37    2016-07-12 16:40 UTC
        + Chg : A large chunk of boilerplate XS code, which is also used in
                other XS modules, has been factored out of the main .xs file
                to a collection of .h files in the xsh subdirectory.
        + Fix : [RT #115392] : Intermittent segfaults with heredocs
                Heredocs should now be handled correctly.
                Thanks Graham Knop for reporting.