"Encouragement" typo in option page

Seen in screenshot of haacked/Encourage#30
https://cloud.githubusercontent.com/assets/430293/3895871/d8ad1f7e-2251-11e4-8f46-a52628f9b7f7.png
Merge pull request #31 from jimgraham/JGFixOptionTypo

"Encouragement" typo in option page