Make convertGrammar() slightly smarter (still pretty dumb), remove wikiquote

Make convertGrammar() slightly smarter (still pretty dumb), remove wikiquote
kluge.  NOTE: This will require setting $wgGrammarForms in LocalSettings.php
at fi.wikiquote as follows:

$wgGrammarForms['fi']['genitive']['Wikisitaatit'] = 'Wikisitaattien';
$wgGrammarForms['fi']['partitive']['Wikisitaatit'] = 'Wikisitaatteja';
$wgGrammarForms['fi']['elative']['Wikisitaatit'] = 'Wikisitaateista';
$wgGrammarForms['fi']['inessive']['Wikisitaatit'] = 'Wikisitaateissa';
$wgGrammarForms['fi']['illative']['Wikisitaatit'] = 'Wikisitaatteihin';