Two bug fixes for process.mixin

Bug #1 occurred when trying to use process.mixin on a function and
produced a fatal exception.

Bug #2 occurred when trying to do a deep merge with an object containing
one or more objects with a nodeType property. In those cases the deep
copy for this part of the object was not performed and a shallow one was
performed instead.

Both of these bugs were artifacts of the jQuery.extend port.

src/node.js

@@ -109,7 +109,7 @@ process.mixin = function() {
 	}
 
 	// Handle case when target is a string or something (possible in deep copy)
-	if ( typeof target !== "object" && !process.isFunction(target) )
+	if ( typeof target !== "object" && !(typeof target === 'function') )
 		target = {};
 
 	// mixin process itself if only one argument is passed
@@ -130,7 +130,7 @@ process.mixin = function() {
 					continue;
 
 				// Recurse if we're merging object values
-				if ( deep && copy && typeof copy === "object" && !copy.nodeType )
+				if ( deep && copy && typeof copy === "object" )
 					target[ name ] = process.mixin( deep, 
 						// Never move original objects, clone them
 						src || ( copy.length != null ? [ ] : { } )

test/mjsunit/test-process-mixin.js

@@ -0,0 +1,16 @@
+process.mixin(require("./common"));
+
+var target = function() {};
+process.mixin(target, {
+  foo: 'bar'
+});
+
+assert.equal('bar', target.foo);
+
+// This test verifies there are no DOM-related aspects to process.mixin which
+// originally had been in there due to its jQuery origin.
+var fakeDomElement = {deep: {nodeType: 4}};
+target = {};
+process.mixin(true, target, fakeDomElement);
+
+assert.notStrictEqual(target.deep, fakeDomElement.deep);