Adding support for require-like initialization of node,

so `node foo`
will load one of:
./foo.js
./foo.node
./foo/index.js
./foo/index.node

Test cases added.
Ensured no conflict with native names.

lib/module.js

@@ -150,8 +150,9 @@ Module._resolveLookupPaths = function(request, parent) {
 
 
 Module._load = function(request, parent) {
-  debug('Module._load REQUEST  ' + (request) +
-        ' parent: ' + parent.id);
+  if (parent) {
+    debug('Module._load REQUEST  ' + (request) + ' parent: ' + parent.id);
+  }
 
   var resolved = Module._resolveFilename(request, parent);
   var id = resolved[0];
@@ -300,7 +301,7 @@ Module._extensions['.node'] = function(module, filename) {
 Module.runMain = function() {
   // Load the main module--the command line argument.
   process.mainModule = new Module('.');
-  process.mainModule.load(process.argv[1]);
+  Module._load(process.argv[1]);
 };
 
 Module._initPaths = function() {

test/fixtures/test-init-index/index.js

@@ -0,0 +1,3 @@
+(function() {
+  require('util').print('Loaded successfully!');
+})();

test/fixtures/test-init-native/fs.js

@@ -0,0 +1,6 @@
+(function() {
+  var fs = require('fs');
+  if (fs.readFile) {
+    require('util').print('fs loaded successfully');
+  }
+})();

test/message/undefined_reference_in_new_context.out

@@ -9,5 +9,6 @@ ReferenceError: foo is not defined
     at Module._compile (module.js:*)
     at Object..js (module.js:*)
     at Module.load (module.js:*)
+    at Function._load (module.js:178:10)
     at Array.<anonymous> (module.js:*)
     at EventEmitter._tickCallback (node.js:*)

test/simple/test-init.js

@@ -0,0 +1,39 @@
+(function() {
+  var assert = require('assert'),
+      child  = require('child_process'),
+      util   = require('util'),
+      common = require('../common');
+  if (process.env['TEST_INIT']) {
+    util.print('Loaded successfully!');
+  } else {
+    // change CWD as we do this test so its not dependant on current CWD
+    // being in the test folder
+    process.chdir(__dirname);
+
+    child.exec(process.execPath + ' test-init',{env:{'TEST_INIT':1}},
+    function(err, stdout, stderr) {
+      assert.equal(stdout, 'Loaded successfully!', '`node test-init` failed!');
+    });
+    child.exec(process.execPath + ' test-init.js', {env:{'TEST_INIT':1}},
+    function(err, stdout, stderr) {
+      assert.equal(stdout, 'Loaded successfully!', '`node test-init.js` failed!');
+    });
+
+    // test-init-index is in fixtures dir as requested by ry, so go there
+    process.chdir(common.fixturesDir);
+
+    child.exec(process.execPath + ' test-init-index',{env:{'TEST_INIT':1}},
+    function(err, stdout, stderr) {
+      assert.equal(stdout, 'Loaded successfully!', '`node test-init-index failed!');
+    });
+
+    // ensures that `node fs` does not mistakenly load the native 'fs' module
+    // instead of the desired file and that the fs module loads as expected in node
+    process.chdir(common.fixturesDir + '/test-init-native/');
+
+    child.exec(process.execPath + ' fs', {env:{'TEST_INIT':1}},
+    function(err, stdout, stderr) {
+      assert.equal(stdout, 'fs loaded successfully', '`node fs` failed!');
+    });
+  }
+})();