Add support for non-lowercase tag-names

Previously, all tag-names were lower-cased, however, this behaviour
conflicts with SVG tag-names.  To allow camel-cased SVG tag-names,
the limitation was lifted, and case normalisation no longer occurs.

Author: wooorm

index.js

@@ -78,7 +78,7 @@ function parse(selector) {
         }
     }
 
-    node.tagName = name.toLowerCase();
+    node.tagName = name;
 
     if (id) {
         node.properties.id = id;

test.js

@@ -97,5 +97,16 @@ test('parseSelector()', function (t) {
         'should return the last ID if multiple are found'
     );
 
+    t.deepEqual(
+        parseSelector('Foo'),
+        {
+            'type': 'element',
+            'tagName': 'Foo',
+            'properties': {},
+            'children': []
+        },
+        'should *not* case the tag-name'
+    );
+
     t.end();
 });