Add note to readme.md: to build with bundle, less@1.7.5 or lower is required

[msikma]

A minor change to the readme.md file would be nice, since this confused me a bit when I tried to build the project using bundle exec jekyll build. The following error was shown (included here for completeness):

Configuration file: /Users/msikma/Source/Font-Awesome/_config.yml
            Source: src
       Destination: _gh_pages
      Generating... Compiling Less files
lessc assets/font-awesome/less/font-awesome.less > assets/font-awesome/css/font-awesome.css
lessc --compress assets/font-awesome/less/font-awesome.less > assets/font-awesome/css/font-awesome.min.css
lessc --yui-compress assets/less/site.less > assets/css/site.css
make: *** [build] Error 1
done.

The problem is that the --yui-compress argument is not supported as of less 2.0.0. So in order to successfully compile the project, the user needs to first do some thing like npm install -g less@1.7.5 (latest pre-2.0.0 version).

It could also be added to the project's dependencies. Alternatively, the build process could be rewritten to work properly with whatever ended up replacing that argument.

[tagliala]

I've explicitly added less and therubyracer to Gemfile in 5.0.0-wip branch

[matriphe]

found the same error like @msikma's. following the suggestion, using npm install -g less@1.7.5 instead of npm install -g less worked like charm!