fixes an issue where "convert file.htm" was failing

wrong
action: 'convert file.html'

right
action: ['convert', 'file.html']
Merge branch 'master' of git://github.com/smhg/grunt-component
Added a test for 'component convert'
Merge pull request #6 from davidtsuji/master

enables specifying additional parameters for an action (closes #5)