Revert "Add lowercase of åäö in entityMap" (#84)

This reverts commit ef20262.

These characters were already included lower in the file in the sorted
order for lower-case runes.

Including duplicates like this causes issues in Rhino 1.7.12:

    Property "auml" already defined in this object literal.

Fixes: #83

lib/entities.js

@@ -9,9 +9,7 @@ exports.entityMap = {
        Acirc: "Â",
        Atilde: "Ã",
        Auml: "Ä",
-       auml: "ä",
        Aring: "Å",
-       aring: "å",
        AElig: "Æ",
        Ccedil: "Ç",
        Egrave: "È",
@@ -29,7 +27,6 @@ exports.entityMap = {
        Ocirc: "Ô",
        Otilde: "Õ",
        Ouml: "Ö",
-       ouml: "ö",
        Oslash: "Ø",
        Ugrave: "Ù",
        Uacute: "Ú",