[stringtemplate-interest] added unicode escapes

[Terence Parr]

Hi. Thanks to Caleb's prodding, we have unicode escapes:

o allows unicode escapes as expression literals but only if it's the  
whole
   expression: <\uFEA5\n\u00C2>  Previously could only do one char and  
just
   the special ones like <\n>.

Benjamin/Kunle: i altered

edit //depot/code/stringtemplate/java/main/CHANGES.txt#8
edit //depot/code/stringtemplate/java/main/src/org/antlr/ 
stringtemplate/language/angle.bracket.template.g#13
edit //depot/code/stringtemplate/java/main/src/org/antlr/ 
stringtemplate/language/template.g#15
edit //depot/code/stringtemplate/java/main/src/org/antlr/ 
stringtemplate/test/TestStringTemplate.java#78
Change 4338 submitted.

This is for 3.1 release.

Ter