Notice of some changes in XS and core UTF-8 handling

New macros have been created in blead for doing character classification 
and character case changing of UTF-8 encoded strings.  For example, 
isALPHA_utf8_safe(), toLOWER_utf8_safe().  These take an extra parameter 
so that the macro can be sure to not read past the end of the string 
when the UTF-8 is malformed.  The existing macros are deprecated, and 
will raise a warning to that effect on the first use in each call point 
of a program.  Details are in perlapi.

Also, handling of some UTF-8 malformations has been changed in the 
bottom level decode routines.  These are unlikely to affect anyone; 
details are in perldelta, and perlapi.

• Notice of some changes in XS and core UTF-8 handling by Karl Williamson