Merge pull request #9 from mglukhovsky/master

Changed the filename parameter for AliasFiles from nil to an empty string.
Add a section on how to use the plugin

I could not find instructions on how to use this plugin. It turned out to be really simple, but it would have been nice to see it in the README here.
Merge pull request #10 from smholloway/patch-1

Updated the README with more explicit instructions.
Fixed a typo and outdated link in the documentation.
Added license details to the README.