Extended character classification

## Macros

#define | SVN_CTYPE_UTF8LEAD 0x0100
| UTF-8 multibyte lead byte.
#define | SVN_CTYPE_UTF8CONT 0x0200
| UTF-8 multibyte non-lead byte.
#define | SVN_CTYPE_UTF8MBC (SVN_CTYPE_UTF8LEAD | SVN_CTYPE_UTF8CONT)
| Part of a UTF-8 multibyte character.
#define | SVN_CTYPE_UTF8 (SVN_CTYPE_ASCII | SVN_CTYPE_UTF8MBC)
| All valid UTF-8 bytes.
#define | svn_ctype_isutf8lead(c) svn_ctype_test((c), SVN_CTYPE_UTF8LEAD)
| Check if c is a UTF-8 multibyte lead byte.
#define | svn_ctype_isutf8cont(c) svn_ctype_test((c), SVN_CTYLE_UTF8CONT)
| Check if c is a UTF-8 multibyte continuation (non-lead) byte.
#define | svn_ctype_isutf8mbc(c) svn_ctype_test((c), SVN_CTYPE_UTF8MBC)
| Check if c is part of a UTF-8 multibyte character.
#define | svn_ctype_isutf8(c) svn_ctype_test((c), SVN_CTYPE_UTF8)
| Check if c is valid in UTF-8.

## Detailed Description