Parentheses examples makes more sense

In the old example, parentheses had no impact because multiplication should have precedence over addition.

Thanks to @inseo for the suggestion.
Merge pull request #770 from kaelig/patch-1

Parentheses example make more sense
Don't strip bangs from loud comments (closes: #784)
Merge branch 'loud_comments' of https://github.com/superlukas/sass into superlukas-loud_comments

Conflicts:
	lib/sass/engine.rb
Merge branch 'superlukas-loud_comments'