SASS support and automatic SASS build

There is a great SASS plugin for Sublime Text (https://github.com/nathos/sass-textmate-bundle), but unfortunately the SASS Build Plugin (https://github.com/jaumefontal/SASS-Build-SublimeText2) does only work on OSx if you put the following in the SASS.sublime-build file:

{
    "cmd": ["sass", "--update", "$file"],  
    "working_dir": "$file_path",  
    "selector": ["source.scss", "source.sass"]
}

Don't forget to install the sass gem:

gem install sass

Then you have to choices:
1. Either you use the additional SaveOnBuild Plugin: https://github.com/alexnj/SublimeOnSaveBuild
2. or you change the above cmd parameter to start a background process that watches for changes:

"cmd": ["sass", "--watch", "$file"]