Don't remove namespace attributes when registering

When registering namespaces from an attributes list the attributes should _not_
be removed.

This fixes #45.

lib/oga/xml/element.rb

@@ -285,15 +285,12 @@ module Oga
       # has been registered the corresponding attribute is removed.
       #
       def register_namespaces_from_attributes
-        self.attributes = attributes.reject do |attr|
+        attributes.each do |attr|
           # We're using `namespace_name` opposed to `namespace.name` as "xmlns"
           # is not a registered namespace.
-          remove = attr.name == XMLNS_PREFIX ||
+          if attr.name == XMLNS_PREFIX or attr.namespace_name == XMLNS_PREFIX
-            attr.namespace_name == XMLNS_PREFIX
+            register_namespace(attr.name, attr.value)
-
+          end
-          register_namespace(attr.name, attr.value) if remove
-
-          remove
         end
       end
 

spec/oga/xml/element_spec.rb

@@ -29,8 +29,8 @@ describe Oga::XML::Element do
       @element.namespaces['foo'].is_a?(Oga::XML::Namespace).should == true
     end
 
-    example 'remove the namespace attribute from the list of attributes' do
+    example 'keep the attributes after registering the namespaces' do
-      @element.attributes.empty?.should == true
+      @element.attributes.empty?.should == false
     end
   end
 
@@ -44,10 +44,6 @@ describe Oga::XML::Element do
     example 'register the default namespace' do
       @element.namespaces['xmlns'].is_a?(Oga::XML::Namespace).should == true
     end
-
-    example 'remove the namespace attribute from the list of attributes' do
-      @element.attributes.empty?.should == true
-    end
   end
 
   context '#attribute' do