Add info about re-compiling XS modules

Add an answer to the question 'Do I need to recompile XS modules when there is
a change in the C library', as documented by Mike Doherty.  I've also updated
the copyright year range to include the current year.

Reference: https://github.com/perl-doc-cats/perlfaq/issues/36
Update answer as per feedback
Merge pull request #43 from talexb/docUpdate-0807

Thanks - I'll remove the (contributed ...) bit later and put that info in the Changes file - before I actually do a release