Update to Font Awesome 3.2.1 (Issue #16)

Update to Font Awesome 3.2.1

**Summary:**

* Updated all font and css assets to Font Awesome version 3.2.1
* Added a .gitignore for OSX .DS_Store
* Updated the PDF CheatSheet to version 3.2.1
* Updated the build/icons.yml to version 3.2.1
* Bumped the wordpress plugin version to 3.2.1
* Updated the README where relevant and included v3.2.1 release notes

FYI - Previous pull request contained a markdown error in the README which I've since corrected. Hence the resubmit.