Refactor minor changes in documentation
Fix wrong function signature of copyStyle()
Correct use and implementation of calculateOffset()
Correct identifier typo

Incorrectly referencing `event` instead of `$event` while determining the target
of a click event on the document body resulted in the character picker overlay
always being hidden after every mouse click in IE--even if the event target was
the characterpicker "open" button.
Remove useless code
Revert "Fix wrong function signature of copyStyle()"

Defer this improvement for a non-hotfix release.

This reverts commit 6ec76b0cd7819044ae7f6f09f8dc29b4f2bb32f6.
Revert "Correct use and implementation of calculateOffset()"

Defer this improvement for a non-hotfix release.

This reverts commit 7faabc27dcd0700ae240a21f1e8d884f9a7c43a4.
Revert "Remove useless code"

Defer this improvement for a non-hotfix release.

This reverts commit 8e13eacb46f5c868b7c34efe286d370ea70974fb.