Support for scope in during() and after() methods

Added support for function call scope in case of after and during methods.

I'm basically integrating svg JS with an Ext Js project, and this feature has great value in such a case.

With this addition the two callback methods can be used either with the original signature (ie. only a function is provided) or by passing an anonymous object with a scope field, and an fn field representing the scope and the function to be called respectively.

{
scope: [function call scope],
fn: [function to be called]
}