Added afterTabChange functionality

[jvb93]

I didn't have time to build duringTabChange, but I really needed afterTabChange for another project so I built it.

[coveralls]

Coverage decreased (-1.04%) to 90.146% when pulling 0fd7bc1 on jvb93:more-event-hooks into 4113999 on cristijora:master.

[jvb93]

You'll have to forgive me, @cristijora, I am not sure how to use this testing framework.

[coveralls]

Coverage decreased (-0.3%) to 90.876% when pulling 7276fcd on jvb93:more-event-hooks into 4113999 on cristijora:master.

[cristijora]

Thanks for the great input @jvb93 No worries about the tests. They are 👍