fixed deprecated usage of generic word-list in for-loop w/o parentheses
improved tab deletion

* old behavior: when closing a tab the last one was focussed
* new behavior: when closing a tab the NEXT one will be focussed
Improved tab moving

* old behavior: when moving a tab was wrapped around at the
  beginning/end the first/last tab was moved to the end/beginning
* new behavior: when reaching the beginning/end the tab will be either
  appended or prepended depending on its position and direction