improve UTF8 suport on Ruby/Tk

[Hidetoshi NAGAI]

Hi,

If you are interested in the following ChangeLog, please try it.

------<ChangeLog>-----------------------------
Thu Oct 16 16:40:51 2003 Hidetoshi NAGAI <[email protected]>

* ext/tk/lib/tk.rb:
Add Tk::EncodedString and Tk::UTF8_String class to support
characters using the \uXXXX escape to the UNICODE string.

* ext/tk/sample/{demos-en,demos-jp}/unicodeout.rb
new demo-scripts (samples of Tk::UTF8_String)

* ext/tk/sample/{demos-en,demos-jp}/widget
add entries for 'unicodeout.rb'