remove unnecessary linefeeds from the end of exception messages

Change-Id: Id1d7971639b2496dbe0274423ff4150d9295e8d6
remove unnecessary NULL parameter passed to UNO Exception

.. now that we have a default value for that parameter

Change-Id: I54d6b0a0a01ce2f2e5168ada0c427424de0477bc
remove more unnecesary OUString constructor use

when throwing exceptions

Change-Id: I6edfb6b6745499f802b0e3c0e096a36fb7c32aac
use OUString::startsWith()

Change-Id: I0fc77b50792e48be175ab7cc151509e097676849