Changes needed for help links in ime menu in ULS extension

* Classes selectable-row and selectable-row-item for consistent styling
* Moved cursor: pointer to more specif rules
* Small comment and code cleanups
* helpHander for options

Made with help of Pau and Santhosh
Undo ime- prefix removals
Merge pull request #214 from Nikerabbit/helplink

Changes needed for help links in ime menu in ULS extension