Clarify README docs.

Fixes #129
current doesn't always return first item in array, reset does
Merge pull request #82 from joostdekeijzer/master

current doesn't always return first item in array, reset does
Removing console.error when history panel is disabled
Transparent icon when toolbar is minimized
Merge pull request #83 from kobake/transparent-icon-when-small

Transparent icon when toolbar is hidden