Remove unnecessary documentation from coffee-mode-hook

Such configuration should not be defined in hook,
they should be defined in `eval-after-load`.
Merge pull request #210 from defunkt/remove-unnecessary-documentation

Remove unnecessary documentation from coffee-mode-hook
Update document

- add information of indentation variable `coffee-tab-width`
- add sample configuration
Merge pull request #211 from defunkt/update-documentation

Update document
Fix source map issue(#212)

We should not specify '-j' option for compiling to JavaScript.
It should be used only Rails '.js.coffee' file for avoiding
'.js.js' file generated.

If you want to generate source map file in Rails project,
please see following project.

  https://github.com/markbates/coffee-rails-source-maps
Merge pull request #213 from defunkt/fix-sourcemap-issue

Fix source map issue(#212)