feat: build tooltip cell

Author: ElliottAYoung

app/cells/plugins/core/tooltip/show.haml

@@ -0,0 +1,3 @@
+.icon.material-icons.tooltip-icon{ :id => tooltip_id } help
+.mdl-tooltip{ "data-mdl-for" => tooltip_id }
+  = @options[:tooltip]

app/cells/plugins/core/tooltip_cell.rb

@@ -0,0 +1,15 @@
+module Plugins
+  module Core
+    class TooltipCell < Plugins::Core::Cell
+      def show
+        render
+      end
+
+      private
+
+      def tooltip_id
+        @options[:id].parameterize('_')
+      end
+    end
+  end
+end