Add Firefox extension, how to use is in main comment

Extensions in Firefox are not so easy to set up or use:

1) Create a new Firefox profile
  - From the console, run:
    /Applications/Firefox.app/Contents/MacOS/firefox-bin -profilemanager
  - Create a new profile, I named mine Dev

2) Find the new profile folder and open the profile directory you just made
  - ~/Library/Application Support/Firefox/Profiles/

3) Create a 'link' to the Firefox path
  - Open install.rdf
  - Note the value of the em:id tag: {e01419b7-7356-4e56-bead-83397c002926}
  - In your Firefox profile directory, open the extension directory
  - create a file named {e01419b7-7356-4e56-bead-83397c002926}
  - within the file, type the path to our extension_firefox directory. For me:
    ~/Dropbox/launchacademy/error_searcher/extension_firefox/

4) All, goes well, when you re-open Firefox, you will get a prompt for a new
   extension.  After installing the extension, look for Hello, World in the
   status bar

5) Otherwise, open Tools -> Web Developer -> Browser Console
  - You should see errors pertaining to the extension