Same column names

[muratcakmaksoftware]

Hello, I encountered basic a problem.
And I thought the problem maybe I can fix it.
#312

[jbeales]

I have this problem too - and this fix would work for me.

An alternate approach that would also work for me would be to let Rap2hpoutre\FastExcel\Importable::import() and therefore Rap2hpoutre\FastExcel\Importable::importSheet() accept a header callback, or to pass the headers to the existing callback so they can be modified.