Glib::xsapi

[muppet <scott asofyet org>]

committed today a rather large change to the comments in the Glib 
module.

moved all the gtk-doc comments from gperl.h into the various xs files 
as embedded POD.  this means the comments are closer to the code and 
thus more likely to be kept synchronized (however slightly that may be).

the drawback is that gperl.h is no longer heavily commented.

the advantage is that the Makefile now uses podselect to extract the 
POD from all of the XS files and create Glib::xsapi, a new installable 
documentation page for the xs api reference.

a preview version, stripped from my working directory just now, is 
available at
http://gtk2-perl.sourceforge.net/doc/Glib::xsapi.html


as always, let me know what you think.