removed 'yield' from the reserved keywords
added 'yield' to the unary keywords
using 'yield' automatically turns functions into generators
added a test for generators
removed yield from the reserved words
npm run-script test-harmony executes generator tests
improved readability of generator test
entire generator test file is now ignored if generators are not available
improved readability of cakefile generator check
further improved readability of cakefile generator check
fixed misspelling in Cakefile
Merge github.com:jashkenas/coffee-script
first attempt at using '->*" and '=>*' for generators
'->*' and '=>*' now produce generators
first attempt at including 'yield*'
updated lexer to allow 'yield*'
'yield*' now works as expected
Merge https://github.com/jashkenas/coffee-script

Conflicts:
	lib/coffee-script/lexer.js
	lib/coffee-script/parser.js
	lib/coffee-script/rewriter.js
	src/lexer.coffee
	src/rewriter.coffee
Add tests for the optimization of trailing return statements

This documents current behavior. When #1038 was fixed, we also optimized
away trailing "undefined" and "return undefined", but that is no longer
the case.
Remove reference to never-defined .isUndefined property

This was added in f4a7cca0755b61fe70db0f7dc5b841aec44022ae to fix #1038
for CoffeeScript 1.0.1. `.isUndefined` was removed in
caf3da2f664f65f3aead70a6292385dea18da9ba but this code was never
updated. That actually caused the behavior of this code to change
(trailing `undefined` and `return undefined` statements no longer got
optimized away) when CoffeeScript 1.3.2 was released, but the new
behavior was deemed correct in
https://github.com/jashkenas/coffee-script/issues/1038#issuecomment-14427560.