Introducing new collations:
utf8_general_mysql500_ci and ucs2_general_mysql500_ci,
to reproduce behaviour of utf8_general_ci and ucs2_general_ci
from mysql-5.1.23 (and earlier).

The collations are added to simplify upgrade from mysql-5.1.23 and earlier.

Note: The patch does not make new server start over old data automatically.
Some manual upgrade procedures are assumed.

Paul: please get in touch with me to discuss upgrade procedures
when documenting this bug.

modified:
  include/m_ctype.h
  mysql-test/r/ctype_utf8.result
  mysql-test/t/ctype_utf8.test
  mysys/charset-def.c
  strings/ctype-ucs2.c
  strings/ctype-utf8.c