feat(ngDocs): add links to source for API

 - add tests
 - the link points to the gruntUtil.getVersion().number tree on github

docs/spec/sourceLinkSpec.js

@@ -0,0 +1,29 @@
+var ngdoc = require('../src/ngdoc.js');
+var gruntUtil = require('../../lib/grunt/utils.js');
+
+describe('Docs Links', function() {
+
+  describe('links', function() {
+    var doc;
+
+    beforeEach(function() {
+      doc = new ngdoc.Doc("@ngdoc function\n@name ng.filter:a\n@function");
+      doc.section = 'api';
+      doc.file = 'test.js';
+      doc.line = 42;
+      doc.parse();
+    });
+
+    it('should have an "improve this doc" button', function() {
+      expect(doc.html()).
+        toContain('<a href="http://github.com/angular/angular.js/edit/master/test.js" class="improve-docs btn btn-primary"><i class="icon-edit"> </i> Improve this doc</a>');
+    });
+
+    it('should have an "view source" button', function() {
+      expect(doc.html()).
+        toContain('<a href="http://github.com/angular/angular.js/tree/v' + gruntUtil.getVersion().number + '/test.js#L42" class="view-source btn btn-action"><i class="icon-zoom-in"> </i> View source</a>');
+    });
+
+  });
+
+});

docs/src/ngdoc.js

@@ -378,7 +378,16 @@ Doc.prototype = {
     dom.h(title(this.name), function() {
 
       notice('deprecated', 'Deprecated API', self.deprecated);
-      dom.tag('a', {href: 'http://github.com/angular/angular.js/edit/master/' + self.file, class: 'improve-docs btn btn-primary'}, 'Improve this doc');
+      dom.tag('a', {href: 'http://github.com/angular/angular.js/edit/master/' + self.file, class: 'improve-docs btn btn-primary'}, function(dom) {
+        dom.tag('i', {class:'icon-edit'}, ' ');
+        dom.text(' Improve this doc');
+      });
+      if (self.section === 'api') {
+        dom.tag('a', {href: 'http://github.com/angular/angular.js/tree/v' + gruntUtil.getVersion().number + '/' + self.file + '#L' + self.line, class: 'view-source btn btn-action'}, function(dom) {
+          dom.tag('i', {class:'icon-zoom-in'}, ' ');
+          dom.text(' View source');
+        });
+      }
       if (self.ngdoc != 'overview') {
         dom.h('Description', self.description, dom.html);
       }
@@ -401,7 +410,7 @@ Doc.prototype = {
     //////////////////////////
 
     function notice(name, legend, msg){
-      if (self[name] == undefined) return;
+      if (self[name] === undefined) return;
       dom.tag('fieldset', {'class':name}, function(dom){
         dom.tag('legend', legend);
         dom.text(msg);

docs/src/templates/css/docs.css

@@ -95,8 +95,9 @@
 /*            Content              */
 /* =============================== */
 
-.improve-docs {
+.improve-docs, .view-source {
   float: right;
+  margin: 0 5px;
 }
 
 .hint {