C89 compatability for activeperl

Work on #27.

This diff is mostly whitespace. Add brackets to lines 785 and 1028,
and indent the code in between.

Add the headers at the top for slightly better efficiency.
NO_XSLOCKS seems to fix problems on ActiveState Perl/Windows with
memory freeing problems. For one example see:
https://rt.cpan.org/Public/Bug/Display.html?id=62150.

PERL_NO_GET_CONTEXT will allow correctly written code to work better
with multithreaded perls. If it's not a multithreaded per,l the macro
does nothing. I generally include them as a result of some crazy cpan
smoke test combination failure.
Updated Makefile.PL with new version

The version was wrong because of some incomplete release cycles
resulting in missing version tags.

Closes #26.