Some overcomplication in tab component

jQuery collection creation already present in `Tab`, as well as checking for `.data("tab")` presence.
Also, `e` argument is not used in callback and can be removed.
And, obviously, there is no need to save object inside `obj` variable as it will be never used.

Just one line instead of 5, no conditions, no additional variables.

I didn't check other components, but I think such code is much easier to read, understand and maintain.