build(aio): support guide authoring

This commit implements various tags, inline tags and changes the markdown
renderer to use Rho. This enables us to generate guide type documents.

tools/docs/content-package/index.js

@@ -15,6 +15,11 @@ module.exports = new Package('content', [jsdocPackage, linksPackage])
                        readFilesProcessor.fileReaders.push(contentFileReader);
                      })
 
+                     .config(function(parseTagsProcessor, getInjectables) {
+                       parseTagsProcessor.tagDefinitions = parseTagsProcessor.tagDefinitions.concat(
+                           getInjectables(requireFolder('./tag-defs')));
+                     })
+
                      // Configure ids and paths
                      .config(function(computeIdsProcessor, computePathsProcessor) {
 
@@ -33,3 +38,10 @@ module.exports = new Package('content', [jsdocPackage, linksPackage])
                          getAliases: function(doc) { return [doc.id]; }
                        });
                      });
+
+function requireFolder(folderPath) {
+  const absolutePath = path.resolve(__dirname, folderPath);
+  return fs.readdirSync(absolutePath)
+      .filter(p => !/[._]spec\.js$/.test(p))  // ignore spec files
+      .map(p => require(path.resolve(absolutePath, p)));
+}

tools/docs/content-package/readers/content.js

@@ -20,7 +20,7 @@ module.exports = function contentFileReader() {
     getDocs: function(fileInfo) {
 
       // We return a single element array because content files only contain one document
-      return [{docType: 'guide', content: fileInfo.content, startingLine: 1}];
+      return [{docType: 'content', content: fileInfo.content, startingLine: 1}];
     }
   };
 };

tools/docs/content-package/readers/content.spec.js

@@ -37,7 +37,7 @@ describe('contentFileReader', function() {
           'project/path/modules/someModule/foo/docs/subfolder/bar.ngdoc', 'A load of content',
           'project/path');
       expect(fileReader.getDocs(fileInfo)).toEqual([
-        {docType: 'guide', content: 'A load of content', startingLine: 1}
+        {docType: 'content', content: 'A load of content', startingLine: 1}
       ]);
     });
   });

tools/docs/content-package/tag-defs/intro.js

@@ -0,0 +1,3 @@
+module.exports = function() {
+  return {name: 'intro'};
+};

tools/docs/content-package/tag-defs/title.js

@@ -0,0 +1,3 @@
+module.exports = function() {
+  return {name: 'title'};
+};