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.
Register .coffee extension by default on Cakefile
Merge pull request #3368 from ricardobeat/cake-register-by-default

Cakefile: register .coffee extension by default
changelog: add anchor to each section

Add releaseHeader helper to avoid repetition.
changelog: add missing compare view URLs
Merge pull request #3376 from davidchambers/anchors

change log improvements
Rudimentary fix for jashkenas/coffee-script#3379.
Merge pull request #3380 from madprgmr/master

Rudimentary fix for jashkenas/coffee-script#3379.
changelog: replace inline CSS
Merge pull request #3381 from davidchambers/inline-css

changelog: replace inline CSS
changelog: use time elements for release dates
Merge pull request #3382 from davidchambers/time-elements

changelog: use time elements for release dates
Fixes issue #3349, prints deprecation warning

This patch fixes issue #3349, by prints deprecation warning for
users who depends on old(<1.7.0) implicit module registration.
Improved coding convention and messages.
Merge pull request #3386 from blmarket/deprecate_warning

Fixes issue #3349, prints deprecation warning
add newlines to end of files
typo: mult-dot => multi-dot
remove editorialisation
Convert README to Markdown