fix some screw-up with internal vs deck names

Parser::hasKeyword() was called with deckNames but looked up the map
for internal names. This patch renames the method to hasDeckName(),
renames Parser::getKeyword() to Parser::getKeywordFromDeckName() and
adapts/extends the tests.
Merge pull request #251 from andlaus/fix_deck_names_vs_internal_names

fix some screw-up with internal vs deck names