Encapsulate dependencies of stats index page

This may be a bit extreme.

It's modeled after the ideal "rails way".

In the controller, we now know the name of a single resource. It
doesn't happen to be backed by a database table, but it does know all
about the task of collecting stats, leaving the controller concerned
with just munging params and rendering stuff.

I called the resource `IndexPage`, to avoid the temptation of trying to
reuse it, which can get pretty messy.

Later, if a better abstraction appears, it should be fairly painless to
alter.

app/models/stats/index_page.rb

@@ -0,0 +1,43 @@
+module Stats
+  class IndexPage
+
+    attr_reader :user
+    def initialize(user)
+      @user = user
+    end
+
+    def actions
+      @actions ||= Stats::Actions.new(user)
+    end
+
+    def totals
+      @totals ||= Stats::Totals.new(user)
+    end
+
+    def projects
+      @projects ||= Stats::Projects.new(user)
+    end
+
+    def contexts
+      @contexts ||= Stats::Contexts.new(user)
+    end
+
+    def tag_cloud
+      unless @tag_cloud
+        tags = Stats::TagCloudQuery.new(user).result
+        @tag_cloud = Stats::TagCloud.new(tags)
+      end
+      @tag_cloud
+    end
+
+    def tag_cloud_90days
+      unless @tag_cloud_90days
+        cutoff = 3.months.ago.beginning_of_day
+        tags = Stats::TagCloudQuery.new(user, cutoff).result
+        @tag_cloud_90days = Stats::TagCloud.new(tags)
+      end
+      @tag_cloud_90days
+    end
+
+  end
+end