Revert "Delete zotero-better-bibtex-0.1.28.xpi"

This reverts commit 19956012bc741e799955d092183542c7810ab418.
Revert "authorsAlpha cite key corrected to comply with JabRef specification"

This reverts commit eeed534148603ec70dfbf524da6880e03af7e0e5.
Revert "Removed erroneous file"

This reverts commit aab8a6429ce223470fec402f7dae4c3ad2391b36.