fix crash when erasing entry while iterating through vector
fix crash when erasing entry while iterating through vector

Broadcast might result in calling Remove on the same object which erases
the entry from the listeners vector. If we create a copy we can still
iterate through the vector as all iterators are still valid.

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core