Merge pull request #111 from seven-phases-max/master

Features Overview: improved Scope section.
Updates to add improve this section and remove duplication
Rename Editors-and-Plugins.md to editors-and-plugins.md
Rename Frameworks-using-LESS.md to frameworks-using-less.md
Update command-line-usage.md
expand out the rest of the command line options
more content for command line usage
update dependencies
Updated "Scope" section (#110).
initial detail about detached rulesets
Merge branch 'master' of https://github.com/less/less-docs
Added the CSS output for the first example.

Inspired by this SO questtion http://stackoverflow.com/questions/21853647/ (see comments there). I.e. it's not that evidend what result it will be when e actually mix the mixin in.
mixins.md: fixed typo "hen" -> "when"
online-less-compilers.md: added "JS Bin".