* lisp/language/indian.el ("Grantha"): New language environment.
Add composition rules for Grantha. Add sample text and input method.
* lisp/international/fontset.el (script-representative-chars)
(setup-default-fontset): Support Grantha.
* lisp/leim/quail/indian.el ("grantha"): New input method.
* etc/HELLO: Add two Grantha greetings.
* etc/NEWS: Announce the new language environment.