more native font charsets for pango x renderer(#50633)

[HideToshi Tajima <hidetoshi tajima eng sun com>]

Hi,

I have code change in pango x-renderer to support more native
encoded font for jisx0212, jisx0201 and big5 charsets.

The code change is attached to the bugzilla reference #50633,
at the following URL:
    http://bugzilla.gnome.org/showattachment.cgi?attach_id=866

Please review and let me know if this is okay to commit.

We can get some more Unicode code tables from the unicode.org - 
for CNS11643(1, 2 and 15 planes) and 8859-16. They can be also added in
the similar way if necessary.

In addition, native font charsets used in zh_CN.GB18030/zh.GBK locales
may be added if there are Unicode code tables for these charsets, 
gb18030, and gdk1988.1989(?).

Regards,
HideToshi