Improvements for IE7 and production environments

Love this gem, it's exactly what I've been looking for. I did make a few improvements so it works in our Rails app and older IE browsers. 

* Added an option to set custom path for font-face
* Added IE7 support via stylesheet 
* Removed eot-utils dependency, using eotlitetool.py instead (works in IE7-8)
* Added option to generate icons html file (default: false)