fixes #6 toggle info text of focus/blur & refactor

[soulchainer]

Fixes problem about navigating with tab between the info buttons. Now the info buttons show their attached note on focus and hide it on blur, so tab navigation is fine :). And this way it's not necesary to hit a key to show it, so faster for the user also :). I also created a method to refactor the way the change of the note visibility is handled.