Don't swallow exceptions in child process

If this were in place before I started working on #6960,
it could have saved me almost an hour!!

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@22964 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
Fix regular expressions in sidebar filters

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@22968 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
6960: mergecitations has broken copy of MCQ

The MergeCitations batch tool had a cut-and-pasted code
replicating MergeCitationQuery logic. Naturally, it diverged :-)
Removed MergeCitations.Merge and use MergeCitationQuery instead.

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@22969 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
6960: Bless Source with an IndirectCitationBase

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@22970 4ae1f11a-8b86-4847-b8af-ab372f36d1fd