ParserItem: improve the equallity testing code and remove the defaultSet() method

but we still need the m_defaultSet member because NaN == NaN as well
as NaN != NaN...

opm/parser/eclipse/Parser/ParserItem.cpp

@@ -97,24 +97,4 @@ namespace Opm {
     void ParserItem::setDescription(std::string description) {
         m_description = description;
     }
-
-
-    bool ParserItem::defaultSet() const {
-        return m_defaultSet;
-    }
-
-
-    bool ParserItem::equal(const ParserItem& other) const {
-        if (typeid(this) == typeid(&other)) {
-            if ((name() == other.name()) && 
-                (sizeType() == other.sizeType()) &&
-                (m_defaultSet == other.m_defaultSet))
-                return true;
-            else
-                return false;
-        }
-        else
-            return false;
-    }
-
 }