Catch all error trap in editsongform.py, _processLyrics

[Phill]

Hi,

I have been investigating a bug that has been reported on the support tracker (http://support.openlp.org/issues/1906) and I have traced it back to http://bazaar.launchpad.net/~openlp-core/openlp/release-2.0/view/head:/openlp/plugins/songs/forms/editsongform.py#L941

I have seen reports like this before on the support tracker, but have only just been able to narrow it down thanks to this comment: https://bugs.launchpad.net/openlp/+bug/1051890/comments/4 by Jonathan

It appears that this catch all maybe responsible for us being unable to fix several different bugs.

So as Jonathan says:
" We shouldn't ignore/hide these errors, and ideally want to fix the original cause."
"Either that or re-throw the error"

I've created this separate report as Jonathan's comments were kind of hidden, but to me seem quite important.