[nemo-qml-plugin-contacts] Contact search should match despite diacritics

When a contact's details contain diacritics, they should be ignored for
searching purposes.  If the search string contains diacritics, however,
they should be matched by the contact details.
[nemo-qml-plugin-contacts] Only match searches against local part of addresses

The domain of an address is unlikely to be relevant to matching a
specific person.
Merge pull request #60 from matthewvogt/search

[nemo-qml-plugin-contacts] Contact search should match despite diacritics