Updated script to create Audacity.pot with Project-Id-Version
of audacity 2.3.2 and to update the Project-Id-Version in the po files too.
Ran script so as to apply it.
... BSD version of sed doesn't know -r, but does know -E.
BSD versions of head and tail didn't know --lines= but do know -n.
Also changed the mode to executable and added #! line.
