Chapter 00--03: Fix minor typos
Chapter 00--01: Add abstract to XSFun

...and thus get rid of the warning:

    WARNING: Setting ABSTRACT via file 'lib/XSFun.pm' failed
     at /home/mvuets/perl5/lib/perl5/ExtUtils/MakeMaker.pm line 609
Chapter 02: Add missed #include
another small fix
Merge branch 'fix_types'