Extended namespaces for event listeners to support multiple jscrolls on same pane

[mrIllo]

Also contains bugfix for destroy

[ansnisar]

@mrIllo Thanks for the fix +1 @pklauzinski you should merge this into the master branch

Thanks

[jasverix]

Voting for this @pklauzinski

[Enalmada]

I am trying to get jscroll to work with two vertical jscroll columns side by side and this pull request was the solution. Please consider merging this excellent contribution!