Improve includes from opm-parser

Adopting to opm-parser PR#661, add previously missing includes.

https://github.com/OPM/opm-parser/pull/661

tests/test_parser.cpp

@@ -31,6 +31,8 @@
 #include <opm/parser/eclipse/Parser/Parser.hpp>
 #include <opm/parser/eclipse/Parser/ParseMode.hpp>
 #include <opm/parser/eclipse/Deck/Deck.hpp>
+#include <opm/parser/eclipse/Deck/DeckKeyword.hpp>
+#include <opm/parser/eclipse/Deck/DeckRecord.hpp>
 #include <opm/parser/eclipse/Deck/DeckDoubleItem.hpp>
 
 #include <string>