chore(doc-gen): put typescript stuff into its own package

This means that we can now run just the d.ts file generation by running:

```bash
gulp docs/typings
```

In addition the type definition generation was messing with the other docs tasks
so separating it also fixes problems there.

docs/docs-package/processors/createOverviewDump.js

@@ -0,0 +1,24 @@
+var _ = require('lodash');
+
+module.exports = function createOverviewDump() {
+
+  return {
+    $runAfter: ['processing-docs'],
+    $runBefore: ['docs-processed'],
+    $process: function(docs) {
+      var overviewDoc = {
+        id: 'overview-dump',
+        aliases: ['overview-dump'],
+        path: 'overview-dump',
+        outputPath: 'overview-dump.html',
+        modules: []
+      };
+      _.forEach(docs, function(doc) {
+        if ( doc.docType === 'module' ) {
+          overviewDoc.modules.push(doc);
+        }
+      });
+      docs.push(overviewDoc);
+    }
+  };
+};

docs/docs-package/processors/extractTitleFromGuides.js

@@ -0,0 +1,24 @@
+var _ = require('lodash');
+
+module.exports = function extractTitleFromGuides() {
+
+  return {
+    $runAfter: ['processing-docs'],
+    $runBefore: ['docs-processed'],
+    $process: function(docs) {
+      _(docs).forEach(function(doc) {
+        if (doc.docType === 'guide') {
+          doc.name = doc.name || getNameFromHeading(doc.description);
+        }
+      });
+    }
+  };
+};
+
+
+function getNameFromHeading(text) {
+  var match = /^\s*#\s*(.*)/.exec(text);
+  if (match) {
+    return match[1];
+  }
+}

docs/docs-package/processors/generateNavigationDoc.js

@@ -0,0 +1,68 @@
+var _ = require('lodash');
+
+module.exports = function generateNavigationDoc() {
+
+  return {
+    $runAfter: ['docs-processed'],
+    $runBefore: ['rendering-docs'],
+    $process: function(docs) {
+      var modulesDoc = {
+        value: { sections: [] },
+        moduleName: 'navigation-modules',
+        serviceName: 'MODULES',
+        template: 'data-module.template.js',
+        outputPath: 'js/navigation-modules.js'
+      };
+
+      _.forEach(docs, function(doc) {
+        if ( doc.docType === 'module' ) {
+          var moduleNavItem = {
+            path: doc.path,
+            partial: doc.outputPath,
+            name: doc.id,
+            type: 'module',
+            pages: []
+          };
+
+          modulesDoc.value.sections.push(moduleNavItem);
+
+          _.forEach(doc.exports, function(exportDoc) {
+            if (!exportDoc.private) {
+              var exportNavItem = {
+                path: exportDoc.path,
+                partial: exportDoc.outputPath,
+                name: exportDoc.name,
+                type: exportDoc.docType
+              };
+              moduleNavItem.pages.push(exportNavItem);
+            }
+          });
+        }
+      });
+
+      docs.push(modulesDoc);
+
+
+      var guidesDoc = {
+        value: { pages: [] },
+        moduleName: 'navigation-guides',
+        serviceName: 'GUIDES',
+        template: 'data-module.template.js',
+        outputPath: 'js/navigation-guides.js'
+      };
+
+      _.forEach(docs, function(doc) {
+        if ( doc.docType === 'guide' ) {
+          var guideDoc = {
+            path: doc.path,
+            partial: doc.outputPath,
+            name: doc.name,
+            type: 'guide'
+          };
+          guidesDoc.value.pages.push(guideDoc);
+        }
+      });
+      docs.push(guidesDoc);
+    }
+  };
+};